// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/compiler/backend/code-generator.h"

#include "src/assembler-inl.h"
#include "src/callable.h"
#include "src/compiler/backend/code-generator-impl.h"
#include "src/compiler/backend/gap-resolver.h"
#include "src/compiler/node-matchers.h"
#include "src/compiler/osr.h"
#include "src/heap/heap-inl.h" // crbug.com/v8/8499
#include "src/macro-assembler.h"
#include "src/optimized-compilation-info.h"
#include "src/wasm/wasm-code-manager.h"
#include "src/wasm/wasm-objects.h"

namespace v8 {
namespace internal {
    namespace compiler {

#define __ tasm()->

#define kScratchReg ip

        // Adds S390-specific methods to convert InstructionOperands.
        class S390OperandConverter final : public InstructionOperandConverter {
        public:
            S390OperandConverter(CodeGenerator* gen, Instruction* instr)
                : InstructionOperandConverter(gen, instr)
            {
            }

            size_t OutputCount() { return instr_->OutputCount(); }

            bool Is64BitOperand(int index)
            {
                return LocationOperand::cast(instr_->InputAt(index))->representation() == MachineRepresentation::kWord64;
            }

            bool Is32BitOperand(int index)
            {
                return LocationOperand::cast(instr_->InputAt(index))->representation() == MachineRepresentation::kWord32;
            }

            bool CompareLogical() const
            {
                switch (instr_->flags_condition()) {
                case kUnsignedLessThan:
                case kUnsignedGreaterThanOrEqual:
                case kUnsignedLessThanOrEqual:
                case kUnsignedGreaterThan:
                    return true;
                default:
                    return false;
                }
                UNREACHABLE();
            }

            Operand InputImmediate(size_t index)
            {
                Constant constant = ToConstant(instr_->InputAt(index));
                switch (constant.type()) {
                case Constant::kInt32:
                    return Operand(constant.ToInt32());
                case Constant::kFloat32:
                    return Operand::EmbeddedNumber(constant.ToFloat32());
                case Constant::kFloat64:
                    return Operand::EmbeddedNumber(constant.ToFloat64().value());
                case Constant::kInt64:
#if V8_TARGET_ARCH_S390X
                    return Operand(constant.ToInt64());
#endif
                case Constant::kExternalReference:
                    return Operand(constant.ToExternalReference());
                case Constant::kDelayedStringConstant:
                    return Operand::EmbeddedStringConstant(
                        constant.ToDelayedStringConstant());
                case Constant::kHeapObject:
                case Constant::kRpoNumber:
                    break;
                }
                UNREACHABLE();
            }

            MemOperand MemoryOperand(AddressingMode* mode, size_t* first_index)
            {
                const size_t index = *first_index;
                if (mode)
                    *mode = AddressingModeField::decode(instr_->opcode());
                switch (AddressingModeField::decode(instr_->opcode())) {
                case kMode_None:
                    break;
                case kMode_MR:
                    *first_index += 1;
                    return MemOperand(InputRegister(index + 0), 0);
                case kMode_MRI:
                    *first_index += 2;
                    return MemOperand(InputRegister(index + 0), InputInt32(index + 1));
                case kMode_MRR:
                    *first_index += 2;
                    return MemOperand(InputRegister(index + 0), InputRegister(index + 1));
                case kMode_MRRI:
                    *first_index += 3;
                    return MemOperand(InputRegister(index + 0), InputRegister(index + 1),
                        InputInt32(index + 2));
                }
                UNREACHABLE();
            }

            MemOperand MemoryOperand(AddressingMode* mode = nullptr,
                size_t first_index = 0)
            {
                return MemoryOperand(mode, &first_index);
            }

            MemOperand ToMemOperand(InstructionOperand* op) const
            {
                DCHECK_NOT_NULL(op);
                DCHECK(op->IsStackSlot() || op->IsFPStackSlot());
                return SlotToMemOperand(AllocatedOperand::cast(op)->index());
            }

            MemOperand SlotToMemOperand(int slot) const
            {
                FrameOffset offset = frame_access_state()->GetFrameOffset(slot);
                return MemOperand(offset.from_stack_pointer() ? sp : fp, offset.offset());
            }

            MemOperand InputStackSlot(size_t index)
            {
                InstructionOperand* op = instr_->InputAt(index);
                return SlotToMemOperand(AllocatedOperand::cast(op)->index());
            }

            MemOperand InputStackSlot32(size_t index)
            {
#if V8_TARGET_ARCH_S390X && !V8_TARGET_LITTLE_ENDIAN
                // We want to read the 32-bits directly from memory
                MemOperand mem = InputStackSlot(index);
                return MemOperand(mem.rb(), mem.rx(), mem.offset() + 4);
#else
                return InputStackSlot(index);
#endif
            }
        };

        static inline bool HasRegisterOutput(Instruction* instr, int index = 0)
        {
            return instr->OutputCount() > 0 && instr->OutputAt(index)->IsRegister();
        }

        static inline bool HasFPRegisterInput(Instruction* instr, int index)
        {
            return instr->InputAt(index)->IsFPRegister();
        }

        static inline bool HasRegisterInput(Instruction* instr, int index)
        {
            return instr->InputAt(index)->IsRegister() || HasFPRegisterInput(instr, index);
        }

        static inline bool HasImmediateInput(Instruction* instr, size_t index)
        {
            return instr->InputAt(index)->IsImmediate();
        }

        static inline bool HasFPStackSlotInput(Instruction* instr, size_t index)
        {
            return instr->InputAt(index)->IsFPStackSlot();
        }

        static inline bool HasStackSlotInput(Instruction* instr, size_t index)
        {
            return instr->InputAt(index)->IsStackSlot() || HasFPStackSlotInput(instr, index);
        }

        namespace {

            class OutOfLineRecordWrite final : public OutOfLineCode {
            public:
                OutOfLineRecordWrite(CodeGenerator* gen, Register object, Register offset,
                    Register value, Register scratch0, Register scratch1,
                    RecordWriteMode mode, StubCallMode stub_mode)
                    : OutOfLineCode(gen)
                    , object_(object)
                    , offset_(offset)
                    , offset_immediate_(0)
                    , value_(value)
                    , scratch0_(scratch0)
                    , scratch1_(scratch1)
                    , mode_(mode)
                    , stub_mode_(stub_mode)
                    , must_save_lr_(!gen->frame_access_state()->has_frame())
                    , zone_(gen->zone())
                {
                }

                OutOfLineRecordWrite(CodeGenerator* gen, Register object, int32_t offset,
                    Register value, Register scratch0, Register scratch1,
                    RecordWriteMode mode, StubCallMode stub_mode)
                    : OutOfLineCode(gen)
                    , object_(object)
                    , offset_(no_reg)
                    , offset_immediate_(offset)
                    , value_(value)
                    , scratch0_(scratch0)
                    , scratch1_(scratch1)
                    , mode_(mode)
                    , stub_mode_(stub_mode)
                    , must_save_lr_(!gen->frame_access_state()->has_frame())
                    , zone_(gen->zone())
                {
                }

                void Generate() final
                {
                    if (mode_ > RecordWriteMode::kValueIsPointer) {
                        __ JumpIfSmi(value_, exit());
                    }
                    __ CheckPageFlag(value_, scratch0_,
                        MemoryChunk::kPointersToHereAreInterestingMask, eq,
                        exit());
                    if (offset_ == no_reg) {
                        __ AddP(scratch1_, object_, Operand(offset_immediate_));
                    } else {
                        DCHECK_EQ(0, offset_immediate_);
                        __ AddP(scratch1_, object_, offset_);
                    }
                    RememberedSetAction const remembered_set_action = mode_ > RecordWriteMode::kValueIsMap ? EMIT_REMEMBERED_SET
                                                                                                           : OMIT_REMEMBERED_SET;
                    SaveFPRegsMode const save_fp_mode = frame()->DidAllocateDoubleRegisters() ? kSaveFPRegs : kDontSaveFPRegs;
                    if (must_save_lr_) {
                        // We need to save and restore r14 if the frame was elided.
                        __ Push(r14);
                    }
                    if (mode_ == RecordWriteMode::kValueIsEphemeronKey) {
                        __ CallEphemeronKeyBarrier(object_, scratch1_, save_fp_mode);
                    } else if (stub_mode_ == StubCallMode::kCallWasmRuntimeStub) {
                        __ CallRecordWriteStub(object_, scratch1_, remembered_set_action,
                            save_fp_mode, wasm::WasmCode::kWasmRecordWrite);
                    } else {
                        __ CallRecordWriteStub(object_, scratch1_, remembered_set_action,
                            save_fp_mode);
                    }
                    if (must_save_lr_) {
                        // We need to save and restore r14 if the frame was elided.
                        __ Pop(r14);
                    }
                }

            private:
                Register const object_;
                Register const offset_;
                int32_t const offset_immediate_; // Valid if offset_ == no_reg.
                Register const value_;
                Register const scratch0_;
                Register const scratch1_;
                RecordWriteMode const mode_;
                StubCallMode stub_mode_;
                bool must_save_lr_;
                Zone* zone_;
            };

            Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op)
            {
                switch (condition) {
                case kEqual:
                    return eq;
                case kNotEqual:
                    return ne;
                case kUnsignedLessThan:
                    // unsigned number never less than 0
                    if (op == kS390_LoadAndTestWord32 || op == kS390_LoadAndTestWord64)
                        return CC_NOP;
                    V8_FALLTHROUGH;
                case kSignedLessThan:
                    return lt;
                case kUnsignedGreaterThanOrEqual:
                    // unsigned number always greater than or equal 0
                    if (op == kS390_LoadAndTestWord32 || op == kS390_LoadAndTestWord64)
                        return CC_ALWAYS;
                    V8_FALLTHROUGH;
                case kSignedGreaterThanOrEqual:
                    return ge;
                case kUnsignedLessThanOrEqual:
                    // unsigned number never less than 0
                    if (op == kS390_LoadAndTestWord32 || op == kS390_LoadAndTestWord64)
                        return CC_EQ;
                    V8_FALLTHROUGH;
                case kSignedLessThanOrEqual:
                    return le;
                case kUnsignedGreaterThan:
                    // unsigned number always greater than or equal 0
                    if (op == kS390_LoadAndTestWord32 || op == kS390_LoadAndTestWord64)
                        return ne;
                    V8_FALLTHROUGH;
                case kSignedGreaterThan:
                    return gt;
                case kOverflow:
                    // Overflow checked for AddP/SubP only.
                    switch (op) {
                    case kS390_Add32:
                    case kS390_Add64:
                    case kS390_Sub32:
                    case kS390_Sub64:
                    case kS390_Abs64:
                    case kS390_Abs32:
                    case kS390_Mul32:
                        return overflow;
                    default:
                        break;
                    }
                    break;
                case kNotOverflow:
                    switch (op) {
                    case kS390_Add32:
                    case kS390_Add64:
                    case kS390_Sub32:
                    case kS390_Sub64:
                    case kS390_Abs64:
                    case kS390_Abs32:
                    case kS390_Mul32:
                        return nooverflow;
                    default:
                        break;
                    }
                    break;
                default:
                    break;
                }
                UNREACHABLE();
            }

#define GET_MEMOPERAND32(ret, fi)                                           \
    ([&](int& ret) {                                                        \
        AddressingMode mode = AddressingModeField::decode(instr->opcode()); \
        MemOperand mem(r0);                                                 \
        if (mode != kMode_None) {                                           \
            size_t first_index = (fi);                                      \
            mem = i.MemoryOperand(&mode, &first_index);                     \
            ret = first_index;                                              \
        } else {                                                            \
            mem = i.InputStackSlot32(fi);                                   \
        }                                                                   \
        return mem;                                                         \
    })(ret)

#define GET_MEMOPERAND(ret, fi)                                             \
    ([&](int& ret) {                                                        \
        AddressingMode mode = AddressingModeField::decode(instr->opcode()); \
        MemOperand mem(r0);                                                 \
        if (mode != kMode_None) {                                           \
            size_t first_index = (fi);                                      \
            mem = i.MemoryOperand(&mode, &first_index);                     \
            ret = first_index;                                              \
        } else {                                                            \
            mem = i.InputStackSlot(fi);                                     \
        }                                                                   \
        return mem;                                                         \
    })(ret)

#define RRInstr(instr)                                    \
    [&]() {                                               \
        DCHECK(i.OutputRegister() == i.InputRegister(0)); \
        __ instr(i.OutputRegister(), i.InputRegister(1)); \
        return 2;                                         \
    }
#define RIInstr(instr)                                     \
    [&]() {                                                \
        DCHECK(i.OutputRegister() == i.InputRegister(0));  \
        __ instr(i.OutputRegister(), i.InputImmediate(1)); \
        return 2;                                          \
    }
#define RMInstr(instr, GETMEM)                            \
    [&]() {                                               \
        DCHECK(i.OutputRegister() == i.InputRegister(0)); \
        int ret = 2;                                      \
        __ instr(i.OutputRegister(), GETMEM(ret, 1));     \
        return ret;                                       \
    }
#define RM32Instr(instr) RMInstr(instr, GET_MEMOPERAND32)
#define RM64Instr(instr) RMInstr(instr, GET_MEMOPERAND)

#define RRRInstr(instr)                                                       \
    [&]() {                                                                   \
        __ instr(i.OutputRegister(), i.InputRegister(0), i.InputRegister(1)); \
        return 2;                                                             \
    }
#define RRIInstr(instr)                                                        \
    [&]() {                                                                    \
        __ instr(i.OutputRegister(), i.InputRegister(0), i.InputImmediate(1)); \
        return 2;                                                              \
    }
#define RRMInstr(instr, GETMEM)                                           \
    [&]() {                                                               \
        int ret = 2;                                                      \
        __ instr(i.OutputRegister(), i.InputRegister(0), GETMEM(ret, 1)); \
        return ret;                                                       \
    }
#define RRM32Instr(instr) RRMInstr(instr, GET_MEMOPERAND32)
#define RRM64Instr(instr) RRMInstr(instr, GET_MEMOPERAND)

#define DDInstr(instr)                                                \
    [&]() {                                                           \
        DCHECK(i.OutputDoubleRegister() == i.InputDoubleRegister(0)); \
        __ instr(i.OutputDoubleRegister(), i.InputDoubleRegister(1)); \
        return 2;                                                     \
    }

#define DMInstr(instr)                                                \
    [&]() {                                                           \
        DCHECK(i.OutputDoubleRegister() == i.InputDoubleRegister(0)); \
        int ret = 2;                                                  \
        __ instr(i.OutputDoubleRegister(), GET_MEMOPERAND(ret, 1));   \
        return ret;                                                   \
    }

#define DMTInstr(instr)                                               \
    [&]() {                                                           \
        DCHECK(i.OutputDoubleRegister() == i.InputDoubleRegister(0)); \
        int ret = 2;                                                  \
        __ instr(i.OutputDoubleRegister(), GET_MEMOPERAND(ret, 1),    \
            kScratchDoubleReg);                                       \
        return ret;                                                   \
    }

#define R_MInstr(instr)                                       \
    [&]() {                                                   \
        int ret = 2;                                          \
        __ instr(i.OutputRegister(), GET_MEMOPERAND(ret, 0)); \
        return ret;                                           \
    }

#define R_DInstr(instr)                                         \
    [&]() {                                                     \
        __ instr(i.OutputRegister(), i.InputDoubleRegister(0)); \
        return 2;                                               \
    }

#define D_DInstr(instr)                                               \
    [&]() {                                                           \
        __ instr(i.OutputDoubleRegister(), i.InputDoubleRegister(0)); \
        return 2;                                                     \
    }

#define D_MInstr(instr)                                             \
    [&]() {                                                         \
        int ret = 2;                                                \
        __ instr(i.OutputDoubleRegister(), GET_MEMOPERAND(ret, 0)); \
        return ret;                                                 \
    }

#define D_MTInstr(instr)                                           \
    [&]() {                                                        \
        int ret = 2;                                               \
        __ instr(i.OutputDoubleRegister(), GET_MEMOPERAND(ret, 0), \
            kScratchDoubleReg);                                    \
        return ret;                                                \
    }

            static int nullInstr()
            {
                UNREACHABLE();
            }

            template <int numOfOperand, class RType, class MType, class IType>
            static inline int AssembleOp(Instruction* instr, RType r, MType m, IType i)
            {
                AddressingMode mode = AddressingModeField::decode(instr->opcode());
                if (mode != kMode_None || HasStackSlotInput(instr, numOfOperand - 1)) {
                    return m();
                } else if (HasRegisterInput(instr, numOfOperand - 1)) {
                    return r();
                } else if (HasImmediateInput(instr, numOfOperand - 1)) {
                    return i();
                } else {
                    UNREACHABLE();
                }
            }

            template <class _RR, class _RM, class _RI>
            static inline int AssembleBinOp(Instruction* instr, _RR _rr, _RM _rm, _RI _ri)
            {
                return AssembleOp<2>(instr, _rr, _rm, _ri);
            }

            template <class _R, class _M, class _I>
            static inline int AssembleUnaryOp(Instruction* instr, _R _r, _M _m, _I _i)
            {
                return AssembleOp<1>(instr, _r, _m, _i);
            }

#define ASSEMBLE_BIN_OP(_rr, _rm, _ri) AssembleBinOp(instr, _rr, _rm, _ri)
#define ASSEMBLE_UNARY_OP(_r, _m, _i) AssembleUnaryOp(instr, _r, _m, _i)

#ifdef V8_TARGET_ARCH_S390X
#define CHECK_AND_ZERO_EXT_OUTPUT(num)                         \
    ([&](int index) {                                          \
        DCHECK(HasImmediateInput(instr, (index)));             \
        int doZeroExt = i.InputInt32(index);                   \
        if (doZeroExt)                                         \
            __ LoadlW(i.OutputRegister(), i.OutputRegister()); \
    })(num)

#define ASSEMBLE_BIN32_OP(_rr, _rm, _ri)                                \
    {                                                                   \
        CHECK_AND_ZERO_EXT_OUTPUT(AssembleBinOp(instr, _rr, _rm, _ri)); \
    }
#else
#define ASSEMBLE_BIN32_OP ASSEMBLE_BIN_OP
#define CHECK_AND_ZERO_EXT_OUTPUT(num)
#endif

        } // namespace

#define ASSEMBLE_FLOAT_UNOP(asm_instr)                                    \
    do {                                                                  \
        __ asm_instr(i.OutputDoubleRegister(), i.InputDoubleRegister(0)); \
    } while (0)

#define ASSEMBLE_FLOAT_BINOP(asm_instr)                                  \
    do {                                                                 \
        __ asm_instr(i.OutputDoubleRegister(), i.InputDoubleRegister(0), \
            i.InputDoubleRegister(1));                                   \
    } while (0)

#define ASSEMBLE_COMPARE(cmp_instr, cmpl_instr)                             \
    do {                                                                    \
        AddressingMode mode = AddressingModeField::decode(instr->opcode()); \
        if (mode != kMode_None) {                                           \
            size_t first_index = 1;                                         \
            MemOperand operand = i.MemoryOperand(&mode, &first_index);      \
            if (i.CompareLogical()) {                                       \
                __ cmpl_instr(i.InputRegister(0), operand);                 \
            } else {                                                        \
                __ cmp_instr(i.InputRegister(0), operand);                  \
            }                                                               \
        } else if (HasRegisterInput(instr, 1)) {                            \
            if (i.CompareLogical()) {                                       \
                __ cmpl_instr(i.InputRegister(0), i.InputRegister(1));      \
            } else {                                                        \
                __ cmp_instr(i.InputRegister(0), i.InputRegister(1));       \
            }                                                               \
        } else if (HasImmediateInput(instr, 1)) {                           \
            if (i.CompareLogical()) {                                       \
                __ cmpl_instr(i.InputRegister(0), i.InputImmediate(1));     \
            } else {                                                        \
                __ cmp_instr(i.InputRegister(0), i.InputImmediate(1));      \
            }                                                               \
        } else {                                                            \
            DCHECK(HasStackSlotInput(instr, 1));                            \
            if (i.CompareLogical()) {                                       \
                __ cmpl_instr(i.InputRegister(0), i.InputStackSlot(1));     \
            } else {                                                        \
                __ cmp_instr(i.InputRegister(0), i.InputStackSlot(1));      \
            }                                                               \
        }                                                                   \
    } while (0)

#define ASSEMBLE_COMPARE32(cmp_instr, cmpl_instr)                           \
    do {                                                                    \
        AddressingMode mode = AddressingModeField::decode(instr->opcode()); \
        if (mode != kMode_None) {                                           \
            size_t first_index = 1;                                         \
            MemOperand operand = i.MemoryOperand(&mode, &first_index);      \
            if (i.CompareLogical()) {                                       \
                __ cmpl_instr(i.InputRegister(0), operand);                 \
            } else {                                                        \
                __ cmp_instr(i.InputRegister(0), operand);                  \
            }                                                               \
        } else if (HasRegisterInput(instr, 1)) {                            \
            if (i.CompareLogical()) {                                       \
                __ cmpl_instr(i.InputRegister(0), i.InputRegister(1));      \
            } else {                                                        \
                __ cmp_instr(i.InputRegister(0), i.InputRegister(1));       \
            }                                                               \
        } else if (HasImmediateInput(instr, 1)) {                           \
            if (i.CompareLogical()) {                                       \
                __ cmpl_instr(i.InputRegister(0), i.InputImmediate(1));     \
            } else {                                                        \
                __ cmp_instr(i.InputRegister(0), i.InputImmediate(1));      \
            }                                                               \
        } else {                                                            \
            DCHECK(HasStackSlotInput(instr, 1));                            \
            if (i.CompareLogical()) {                                       \
                __ cmpl_instr(i.InputRegister(0), i.InputStackSlot32(1));   \
            } else {                                                        \
                __ cmp_instr(i.InputRegister(0), i.InputStackSlot32(1));    \
            }                                                               \
        }                                                                   \
    } while (0)

#define ASSEMBLE_FLOAT_COMPARE(cmp_rr_instr, cmp_rm_instr, load_instr)           \
    do {                                                                         \
        AddressingMode mode = AddressingModeField::decode(instr->opcode());      \
        if (mode != kMode_None) {                                                \
            size_t first_index = 1;                                              \
            MemOperand operand = i.MemoryOperand(&mode, &first_index);           \
            __ cmp_rm_instr(i.InputDoubleRegister(0), operand);                  \
        } else if (HasFPRegisterInput(instr, 1)) {                               \
            __ cmp_rr_instr(i.InputDoubleRegister(0), i.InputDoubleRegister(1)); \
        } else {                                                                 \
            USE(HasFPStackSlotInput);                                            \
            DCHECK(HasFPStackSlotInput(instr, 1));                               \
            MemOperand operand = i.InputStackSlot(1);                            \
            if (operand.offset() >= 0) {                                         \
                __ cmp_rm_instr(i.InputDoubleRegister(0), operand);              \
            } else {                                                             \
                __ load_instr(kScratchDoubleReg, operand);                       \
                __ cmp_rr_instr(i.InputDoubleRegister(0), kScratchDoubleReg);    \
            }                                                                    \
        }                                                                        \
    } while (0)

// Divide instruction dr will implicity use register pair
// r0 & r1 below.
// R0:R1 = R1 / divisor - R0 remainder
// Copy remainder to output reg
#define ASSEMBLE_MODULO(div_instr, shift_instr) \
    do {                                        \
        __ LoadRR(r0, i.InputRegister(0));      \
        __ shift_instr(r0, Operand(32));        \
        __ div_instr(r0, i.InputRegister(1));   \
        __ LoadlW(i.OutputRegister(), r0);      \
    } while (0)

#define ASSEMBLE_FLOAT_MODULO()                                                 \
    do {                                                                        \
        FrameScope scope(tasm(), StackFrame::MANUAL);                           \
        __ PrepareCallCFunction(0, 2, kScratchReg);                             \
        __ MovToFloatParameters(i.InputDoubleRegister(0),                       \
            i.InputDoubleRegister(1));                                          \
        __ CallCFunction(ExternalReference::mod_two_doubles_operation(), 0, 2); \
        __ MovFromFloatResult(i.OutputDoubleRegister());                        \
    } while (0)

#define ASSEMBLE_IEEE754_UNOP(name)                                                \
    do {                                                                           \
        /* TODO(bmeurer): We should really get rid of this special instruction, */ \
        /* and generate a CallAddress instruction instead. */                      \
        FrameScope scope(tasm(), StackFrame::MANUAL);                              \
        __ PrepareCallCFunction(0, 1, kScratchReg);                                \
        __ MovToFloatParameter(i.InputDoubleRegister(0));                          \
        __ CallCFunction(ExternalReference::ieee754_##name##_function(), 0, 1);    \
        /* Move the result in the double result register. */                       \
        __ MovFromFloatResult(i.OutputDoubleRegister());                           \
    } while (0)

#define ASSEMBLE_IEEE754_BINOP(name)                                               \
    do {                                                                           \
        /* TODO(bmeurer): We should really get rid of this special instruction, */ \
        /* and generate a CallAddress instruction instead. */                      \
        FrameScope scope(tasm(), StackFrame::MANUAL);                              \
        __ PrepareCallCFunction(0, 2, kScratchReg);                                \
        __ MovToFloatParameters(i.InputDoubleRegister(0),                          \
            i.InputDoubleRegister(1));                                             \
        __ CallCFunction(ExternalReference::ieee754_##name##_function(), 0, 2);    \
        /* Move the result in the double result register. */                       \
        __ MovFromFloatResult(i.OutputDoubleRegister());                           \
    } while (0)

#define ASSEMBLE_DOUBLE_MAX()                                              \
    do {                                                                   \
        DoubleRegister left_reg = i.InputDoubleRegister(0);                \
        DoubleRegister right_reg = i.InputDoubleRegister(1);               \
        DoubleRegister result_reg = i.OutputDoubleRegister();              \
        Label check_nan_left, check_zero, return_left, return_right, done; \
        __ cdbr(left_reg, right_reg);                                      \
        __ bunordered(&check_nan_left, Label::kNear);                      \
        __ beq(&check_zero);                                               \
        __ bge(&return_left, Label::kNear);                                \
        __ b(&return_right, Label::kNear);                                 \
                                                                           \
        __ bind(&check_zero);                                              \
        __ lzdr(kDoubleRegZero);                                           \
        __ cdbr(left_reg, kDoubleRegZero);                                 \
        /* left == right != 0. */                                          \
        __ bne(&return_left, Label::kNear);                                \
        /* At this point, both left and right are either 0 or -0. */       \
        /* N.B. The following works because +0 + -0 == +0 */               \
        /* For max we want logical-and of sign bit: (L + R) */             \
        __ ldr(result_reg, left_reg);                                      \
        __ adbr(result_reg, right_reg);                                    \
        __ b(&done, Label::kNear);                                         \
                                                                           \
        __ bind(&check_nan_left);                                          \
        __ cdbr(left_reg, left_reg);                                       \
        /* left == NaN. */                                                 \
        __ bunordered(&return_left, Label::kNear);                         \
                                                                           \
        __ bind(&return_right);                                            \
        if (right_reg != result_reg) {                                     \
            __ ldr(result_reg, right_reg);                                 \
        }                                                                  \
        __ b(&done, Label::kNear);                                         \
                                                                           \
        __ bind(&return_left);                                             \
        if (left_reg != result_reg) {                                      \
            __ ldr(result_reg, left_reg);                                  \
        }                                                                  \
        __ bind(&done);                                                    \
    } while (0)

#define ASSEMBLE_DOUBLE_MIN()                                              \
    do {                                                                   \
        DoubleRegister left_reg = i.InputDoubleRegister(0);                \
        DoubleRegister right_reg = i.InputDoubleRegister(1);               \
        DoubleRegister result_reg = i.OutputDoubleRegister();              \
        Label check_nan_left, check_zero, return_left, return_right, done; \
        __ cdbr(left_reg, right_reg);                                      \
        __ bunordered(&check_nan_left, Label::kNear);                      \
        __ beq(&check_zero);                                               \
        __ ble(&return_left, Label::kNear);                                \
        __ b(&return_right, Label::kNear);                                 \
                                                                           \
        __ bind(&check_zero);                                              \
        __ lzdr(kDoubleRegZero);                                           \
        __ cdbr(left_reg, kDoubleRegZero);                                 \
        /* left == right != 0. */                                          \
        __ bne(&return_left, Label::kNear);                                \
        /* At this point, both left and right are either 0 or -0. */       \
        /* N.B. The following works because +0 + -0 == +0 */               \
        /* For min we want logical-or of sign bit: -(-L + -R) */           \
        __ lcdbr(left_reg, left_reg);                                      \
        __ ldr(result_reg, left_reg);                                      \
        if (left_reg == right_reg) {                                       \
            __ adbr(result_reg, right_reg);                                \
        } else {                                                           \
            __ sdbr(result_reg, right_reg);                                \
        }                                                                  \
        __ lcdbr(result_reg, result_reg);                                  \
        __ b(&done, Label::kNear);                                         \
                                                                           \
        __ bind(&check_nan_left);                                          \
        __ cdbr(left_reg, left_reg);                                       \
        /* left == NaN. */                                                 \
        __ bunordered(&return_left, Label::kNear);                         \
                                                                           \
        __ bind(&return_right);                                            \
        if (right_reg != result_reg) {                                     \
            __ ldr(result_reg, right_reg);                                 \
        }                                                                  \
        __ b(&done, Label::kNear);                                         \
                                                                           \
        __ bind(&return_left);                                             \
        if (left_reg != result_reg) {                                      \
            __ ldr(result_reg, left_reg);                                  \
        }                                                                  \
        __ bind(&done);                                                    \
    } while (0)

#define ASSEMBLE_FLOAT_MAX()                                               \
    do {                                                                   \
        DoubleRegister left_reg = i.InputDoubleRegister(0);                \
        DoubleRegister right_reg = i.InputDoubleRegister(1);               \
        DoubleRegister result_reg = i.OutputDoubleRegister();              \
        Label check_nan_left, check_zero, return_left, return_right, done; \
        __ cebr(left_reg, right_reg);                                      \
        __ bunordered(&check_nan_left, Label::kNear);                      \
        __ beq(&check_zero);                                               \
        __ bge(&return_left, Label::kNear);                                \
        __ b(&return_right, Label::kNear);                                 \
                                                                           \
        __ bind(&check_zero);                                              \
        __ lzdr(kDoubleRegZero);                                           \
        __ cebr(left_reg, kDoubleRegZero);                                 \
        /* left == right != 0. */                                          \
        __ bne(&return_left, Label::kNear);                                \
        /* At this point, both left and right are either 0 or -0. */       \
        /* N.B. The following works because +0 + -0 == +0 */               \
        /* For max we want logical-and of sign bit: (L + R) */             \
        __ ldr(result_reg, left_reg);                                      \
        __ aebr(result_reg, right_reg);                                    \
        __ b(&done, Label::kNear);                                         \
                                                                           \
        __ bind(&check_nan_left);                                          \
        __ cebr(left_reg, left_reg);                                       \
        /* left == NaN. */                                                 \
        __ bunordered(&return_left, Label::kNear);                         \
                                                                           \
        __ bind(&return_right);                                            \
        if (right_reg != result_reg) {                                     \
            __ ldr(result_reg, right_reg);                                 \
        }                                                                  \
        __ b(&done, Label::kNear);                                         \
                                                                           \
        __ bind(&return_left);                                             \
        if (left_reg != result_reg) {                                      \
            __ ldr(result_reg, left_reg);                                  \
        }                                                                  \
        __ bind(&done);                                                    \
    } while (0)

#define ASSEMBLE_FLOAT_MIN()                                               \
    do {                                                                   \
        DoubleRegister left_reg = i.InputDoubleRegister(0);                \
        DoubleRegister right_reg = i.InputDoubleRegister(1);               \
        DoubleRegister result_reg = i.OutputDoubleRegister();              \
        Label check_nan_left, check_zero, return_left, return_right, done; \
        __ cebr(left_reg, right_reg);                                      \
        __ bunordered(&check_nan_left, Label::kNear);                      \
        __ beq(&check_zero);                                               \
        __ ble(&return_left, Label::kNear);                                \
        __ b(&return_right, Label::kNear);                                 \
                                                                           \
        __ bind(&check_zero);                                              \
        __ lzdr(kDoubleRegZero);                                           \
        __ cebr(left_reg, kDoubleRegZero);                                 \
        /* left == right != 0. */                                          \
        __ bne(&return_left, Label::kNear);                                \
        /* At this point, both left and right are either 0 or -0. */       \
        /* N.B. The following works because +0 + -0 == +0 */               \
        /* For min we want logical-or of sign bit: -(-L + -R) */           \
        __ lcebr(left_reg, left_reg);                                      \
        __ ldr(result_reg, left_reg);                                      \
        if (left_reg == right_reg) {                                       \
            __ aebr(result_reg, right_reg);                                \
        } else {                                                           \
            __ sebr(result_reg, right_reg);                                \
        }                                                                  \
        __ lcebr(result_reg, result_reg);                                  \
        __ b(&done, Label::kNear);                                         \
                                                                           \
        __ bind(&check_nan_left);                                          \
        __ cebr(left_reg, left_reg);                                       \
        /* left == NaN. */                                                 \
        __ bunordered(&return_left, Label::kNear);                         \
                                                                           \
        __ bind(&return_right);                                            \
        if (right_reg != result_reg) {                                     \
            __ ldr(result_reg, right_reg);                                 \
        }                                                                  \
        __ b(&done, Label::kNear);                                         \
                                                                           \
        __ bind(&return_left);                                             \
        if (left_reg != result_reg) {                                      \
            __ ldr(result_reg, left_reg);                                  \
        }                                                                  \
        __ bind(&done);                                                    \
    } while (0)
//
// Only MRI mode for these instructions available
#define ASSEMBLE_LOAD_FLOAT(asm_instr)                    \
    do {                                                  \
        DoubleRegister result = i.OutputDoubleRegister(); \
        AddressingMode mode = kMode_None;                 \
        MemOperand operand = i.MemoryOperand(&mode);      \
        __ asm_instr(result, operand);                    \
    } while (0)

#define ASSEMBLE_LOAD_INTEGER(asm_instr)             \
    do {                                             \
        Register result = i.OutputRegister();        \
        AddressingMode mode = kMode_None;            \
        MemOperand operand = i.MemoryOperand(&mode); \
        __ asm_instr(result, operand);               \
    } while (0)

#define ASSEMBLE_LOADANDTEST64(asm_instr_rr, asm_instr_rm)                  \
    {                                                                       \
        AddressingMode mode = AddressingModeField::decode(instr->opcode()); \
        Register dst = HasRegisterOutput(instr) ? i.OutputRegister() : r0;  \
        if (mode != kMode_None) {                                           \
            size_t first_index = 0;                                         \
            MemOperand operand = i.MemoryOperand(&mode, &first_index);      \
            __ asm_instr_rm(dst, operand);                                  \
        } else if (HasRegisterInput(instr, 0)) {                            \
            __ asm_instr_rr(dst, i.InputRegister(0));                       \
        } else {                                                            \
            DCHECK(HasStackSlotInput(instr, 0));                            \
            __ asm_instr_rm(dst, i.InputStackSlot(0));                      \
        }                                                                   \
    }

#define ASSEMBLE_LOADANDTEST32(asm_instr_rr, asm_instr_rm)                  \
    {                                                                       \
        AddressingMode mode = AddressingModeField::decode(instr->opcode()); \
        Register dst = HasRegisterOutput(instr) ? i.OutputRegister() : r0;  \
        if (mode != kMode_None) {                                           \
            size_t first_index = 0;                                         \
            MemOperand operand = i.MemoryOperand(&mode, &first_index);      \
            __ asm_instr_rm(dst, operand);                                  \
        } else if (HasRegisterInput(instr, 0)) {                            \
            __ asm_instr_rr(dst, i.InputRegister(0));                       \
        } else {                                                            \
            DCHECK(HasStackSlotInput(instr, 0));                            \
            __ asm_instr_rm(dst, i.InputStackSlot32(0));                    \
        }                                                                   \
    }

#define ASSEMBLE_STORE_FLOAT32()                             \
    do {                                                     \
        size_t index = 0;                                    \
        AddressingMode mode = kMode_None;                    \
        MemOperand operand = i.MemoryOperand(&mode, &index); \
        DoubleRegister value = i.InputDoubleRegister(index); \
        __ StoreFloat32(value, operand);                     \
    } while (0)

#define ASSEMBLE_STORE_DOUBLE()                              \
    do {                                                     \
        size_t index = 0;                                    \
        AddressingMode mode = kMode_None;                    \
        MemOperand operand = i.MemoryOperand(&mode, &index); \
        DoubleRegister value = i.InputDoubleRegister(index); \
        __ StoreDouble(value, operand);                      \
    } while (0)

#define ASSEMBLE_STORE_INTEGER(asm_instr)                    \
    do {                                                     \
        size_t index = 0;                                    \
        AddressingMode mode = kMode_None;                    \
        MemOperand operand = i.MemoryOperand(&mode, &index); \
        Register value = i.InputRegister(index);             \
        __ asm_instr(value, operand);                        \
    } while (0)

#define ATOMIC_COMP_EXCHANGE(start, end, shift_amount, offset)                  \
    {                                                                           \
        __ LoadlW(temp0, MemOperand(addr, offset));                             \
        __ llgfr(temp1, temp0);                                                 \
        __ RotateInsertSelectBits(temp0, old_val, Operand(start), Operand(end), \
            Operand(shift_amount), false);                                      \
        __ RotateInsertSelectBits(temp1, new_val, Operand(start), Operand(end), \
            Operand(shift_amount), false);                                      \
        __ CmpAndSwap(temp0, temp1, MemOperand(addr, offset));                  \
        __ RotateInsertSelectBits(output, temp0, Operand(start + shift_amount), \
            Operand(end + shift_amount),                                        \
            Operand(64 - shift_amount), true);                                  \
    }

#ifdef V8_TARGET_BIG_ENDIAN
#define ATOMIC_COMP_EXCHANGE_BYTE(i)                                 \
    {                                                                \
        constexpr int idx = (i);                                     \
        static_assert(idx <= 3 && idx >= 0, "idx is out of range!"); \
        constexpr int start = 32 + 8 * idx;                          \
        constexpr int end = start + 7;                               \
        constexpr int shift_amount = (3 - idx) * 8;                  \
        ATOMIC_COMP_EXCHANGE(start, end, shift_amount, -idx);        \
    }
#define ATOMIC_COMP_EXCHANGE_HALFWORD(i)                             \
    {                                                                \
        constexpr int idx = (i);                                     \
        static_assert(idx <= 1 && idx >= 0, "idx is out of range!"); \
        constexpr int start = 32 + 16 * idx;                         \
        constexpr int end = start + 15;                              \
        constexpr int shift_amount = (1 - idx) * 16;                 \
        ATOMIC_COMP_EXCHANGE(start, end, shift_amount, -idx * 2);    \
    }
#else
#define ATOMIC_COMP_EXCHANGE_BYTE(i)                                 \
    {                                                                \
        constexpr int idx = (i);                                     \
        static_assert(idx <= 3 && idx >= 0, "idx is out of range!"); \
        constexpr int start = 32 + 8 * (3 - idx);                    \
        constexpr int end = start + 7;                               \
        constexpr int shift_amount = idx * 8;                        \
        ATOMIC_COMP_EXCHANGE(start, end, shift_amount, -idx);        \
    }
#define ATOMIC_COMP_EXCHANGE_HALFWORD(i)                             \
    {                                                                \
        constexpr int idx = (i);                                     \
        static_assert(idx <= 1 && idx >= 0, "idx is out of range!"); \
        constexpr int start = 32 + 16 * (1 - idx);                   \
        constexpr int end = start + 15;                              \
        constexpr int shift_amount = idx * 16;                       \
        ATOMIC_COMP_EXCHANGE(start, end, shift_amount, -idx * 2);    \
    }
#endif

#define ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_BYTE(load_and_ext) \
    do {                                                    \
        Register old_val = i.InputRegister(0);              \
        Register new_val = i.InputRegister(1);              \
        Register output = i.OutputRegister();               \
        Register addr = kScratchReg;                        \
        Register temp0 = r0;                                \
        Register temp1 = r1;                                \
        size_t index = 2;                                   \
        AddressingMode mode = kMode_None;                   \
        MemOperand op = i.MemoryOperand(&mode, &index);     \
        Label three, two, one, done;                        \
        __ lay(addr, op);                                   \
        __ tmll(addr, Operand(3));                          \
        __ b(Condition(1), &three);                         \
        __ b(Condition(2), &two);                           \
        __ b(Condition(4), &one);                           \
        /* ending with 0b00 */                              \
        ATOMIC_COMP_EXCHANGE_BYTE(0);                       \
        __ b(&done);                                        \
        /* ending with 0b01 */                              \
        __ bind(&one);                                      \
        ATOMIC_COMP_EXCHANGE_BYTE(1);                       \
        __ b(&done);                                        \
        /* ending with 0b10 */                              \
        __ bind(&two);                                      \
        ATOMIC_COMP_EXCHANGE_BYTE(2);                       \
        __ b(&done);                                        \
        /* ending with 0b11 */                              \
        __ bind(&three);                                    \
        ATOMIC_COMP_EXCHANGE_BYTE(3);                       \
        __ bind(&done);                                     \
        __ load_and_ext(output, output);                    \
    } while (false)

#define ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_HALFWORD(load_and_ext) \
    do {                                                        \
        Register old_val = i.InputRegister(0);                  \
        Register new_val = i.InputRegister(1);                  \
        Register output = i.OutputRegister();                   \
        Register addr = kScratchReg;                            \
        Register temp0 = r0;                                    \
        Register temp1 = r1;                                    \
        size_t index = 2;                                       \
        AddressingMode mode = kMode_None;                       \
        MemOperand op = i.MemoryOperand(&mode, &index);         \
        Label two, done;                                        \
        __ lay(addr, op);                                       \
        __ tmll(addr, Operand(3));                              \
        __ b(Condition(2), &two);                               \
        ATOMIC_COMP_EXCHANGE_HALFWORD(0);                       \
        __ b(&done);                                            \
        __ bind(&two);                                          \
        ATOMIC_COMP_EXCHANGE_HALFWORD(1);                       \
        __ bind(&done);                                         \
        __ load_and_ext(output, output);                        \
    } while (false)

#define ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_WORD()           \
    do {                                                  \
        Register new_val = i.InputRegister(1);            \
        Register output = i.OutputRegister();             \
        Register addr = kScratchReg;                      \
        size_t index = 2;                                 \
        AddressingMode mode = kMode_None;                 \
        MemOperand op = i.MemoryOperand(&mode, &index);   \
        __ lay(addr, op);                                 \
        __ CmpAndSwap(output, new_val, MemOperand(addr)); \
        __ LoadlW(output, output);                        \
    } while (false)

#define ASSEMBLE_ATOMIC_BINOP_WORD(load_and_op)          \
    do {                                                 \
        Register value = i.InputRegister(2);             \
        Register result = i.OutputRegister(0);           \
        Register addr = r1;                              \
        AddressingMode mode = kMode_None;                \
        MemOperand op = i.MemoryOperand(&mode);          \
        __ lay(addr, op);                                \
        __ load_and_op(result, value, MemOperand(addr)); \
        __ LoadlW(result, result);                       \
    } while (false)

#define ASSEMBLE_ATOMIC_BINOP_WORD64(load_and_op)        \
    do {                                                 \
        Register value = i.InputRegister(2);             \
        Register result = i.OutputRegister(0);           \
        Register addr = r1;                              \
        AddressingMode mode = kMode_None;                \
        MemOperand op = i.MemoryOperand(&mode);          \
        __ lay(addr, op);                                \
        __ load_and_op(result, value, MemOperand(addr)); \
    } while (false)

#define ATOMIC_BIN_OP(bin_inst, offset, shift_amount, start, end)              \
    do {                                                                       \
        Label do_cs;                                                           \
        __ LoadlW(prev, MemOperand(addr, offset));                             \
        __ bind(&do_cs);                                                       \
        __ RotateInsertSelectBits(temp, value, Operand(start), Operand(end),   \
            Operand(static_cast<intptr_t>(shift_amount)),                      \
            true);                                                             \
        __ bin_inst(new_val, prev, temp);                                      \
        __ lr(temp, prev);                                                     \
        __ RotateInsertSelectBits(temp, new_val, Operand(start), Operand(end), \
            Operand::Zero(), false);                                           \
        __ CmpAndSwap(prev, temp, MemOperand(addr, offset));                   \
        __ bne(&do_cs, Label::kNear);                                          \
    } while (false)

#ifdef V8_TARGET_BIG_ENDIAN
#define ATOMIC_BIN_OP_HALFWORD(bin_inst, index, extract_result)    \
    {                                                              \
        constexpr int offset = -(2 * index);                       \
        constexpr int shift_amount = 16 - (index * 16);            \
        constexpr int start = 48 - shift_amount;                   \
        constexpr int end = start + 15;                            \
        ATOMIC_BIN_OP(bin_inst, offset, shift_amount, start, end); \
        extract_result();                                          \
    }
#define ATOMIC_BIN_OP_BYTE(bin_inst, index, extract_result)        \
    {                                                              \
        constexpr int offset = -(index);                           \
        constexpr int shift_amount = 24 - (index * 8);             \
        constexpr int start = 56 - shift_amount;                   \
        constexpr int end = start + 7;                             \
        ATOMIC_BIN_OP(bin_inst, offset, shift_amount, start, end); \
        extract_result();                                          \
    }
#else
#define ATOMIC_BIN_OP_HALFWORD(bin_inst, index, extract_result)    \
    {                                                              \
        constexpr int offset = -(2 * index);                       \
        constexpr int shift_amount = index * 16;                   \
        constexpr int start = 48 - shift_amount;                   \
        constexpr int end = start + 15;                            \
        ATOMIC_BIN_OP(bin_inst, offset, shift_amount, start, end); \
        extract_result();                                          \
    }
#define ATOMIC_BIN_OP_BYTE(bin_inst, index, extract_result)        \
    {                                                              \
        constexpr int offset = -(index);                           \
        constexpr int shift_amount = index * 8;                    \
        constexpr int start = 56 - shift_amount;                   \
        constexpr int end = start + 7;                             \
        ATOMIC_BIN_OP(bin_inst, offset, shift_amount, start, end); \
        extract_result();                                          \
    }
#endif // V8_TARGET_BIG_ENDIAN

#define ASSEMBLE_ATOMIC_BINOP_HALFWORD(bin_inst, extract_result) \
    do {                                                         \
        Register value = i.InputRegister(2);                     \
        Register result = i.OutputRegister(0);                   \
        Register prev = i.TempRegister(0);                       \
        Register new_val = r0;                                   \
        Register addr = r1;                                      \
        Register temp = kScratchReg;                             \
        AddressingMode mode = kMode_None;                        \
        MemOperand op = i.MemoryOperand(&mode);                  \
        Label two, done;                                         \
        __ lay(addr, op);                                        \
        __ tmll(addr, Operand(3));                               \
        __ b(Condition(2), &two);                                \
        /* word boundary */                                      \
        ATOMIC_BIN_OP_HALFWORD(bin_inst, 0, extract_result);     \
        __ b(&done);                                             \
        __ bind(&two);                                           \
        /* halfword boundary */                                  \
        ATOMIC_BIN_OP_HALFWORD(bin_inst, 1, extract_result);     \
        __ bind(&done);                                          \
    } while (false)

#define ASSEMBLE_ATOMIC_BINOP_BYTE(bin_inst, extract_result) \
    do {                                                     \
        Register value = i.InputRegister(2);                 \
        Register result = i.OutputRegister(0);               \
        Register addr = i.TempRegister(0);                   \
        Register prev = r0;                                  \
        Register new_val = r1;                               \
        Register temp = kScratchReg;                         \
        AddressingMode mode = kMode_None;                    \
        MemOperand op = i.MemoryOperand(&mode);              \
        Label done, one, two, three;                         \
        __ lay(addr, op);                                    \
        __ tmll(addr, Operand(3));                           \
        __ b(Condition(1), &three);                          \
        __ b(Condition(2), &two);                            \
        __ b(Condition(4), &one);                            \
        /* ending with 0b00 (word boundary) */               \
        ATOMIC_BIN_OP_BYTE(bin_inst, 0, extract_result);     \
        __ b(&done);                                         \
        /* ending with 0b01 */                               \
        __ bind(&one);                                       \
        ATOMIC_BIN_OP_BYTE(bin_inst, 1, extract_result);     \
        __ b(&done);                                         \
        /* ending with 0b10 (hw boundary) */                 \
        __ bind(&two);                                       \
        ATOMIC_BIN_OP_BYTE(bin_inst, 2, extract_result);     \
        __ b(&done);                                         \
        /* ending with 0b11 */                               \
        __ bind(&three);                                     \
        ATOMIC_BIN_OP_BYTE(bin_inst, 3, extract_result);     \
        __ bind(&done);                                      \
    } while (false)

#define ASSEMBLE_ATOMIC64_COMP_EXCHANGE_WORD64()            \
    do {                                                    \
        Register new_val = i.InputRegister(1);              \
        Register output = i.OutputRegister();               \
        Register addr = kScratchReg;                        \
        size_t index = 2;                                   \
        AddressingMode mode = kMode_None;                   \
        MemOperand op = i.MemoryOperand(&mode, &index);     \
        __ lay(addr, op);                                   \
        __ CmpAndSwap64(output, new_val, MemOperand(addr)); \
    } while (false)

        void CodeGenerator::AssembleDeconstructFrame()
        {
            __ LeaveFrame(StackFrame::MANUAL);
        }

        void CodeGenerator::AssemblePrepareTailCall()
        {
            if (frame_access_state()->has_frame()) {
                __ RestoreFrameStateForTailCall();
            }
            frame_access_state()->SetFrameAccessToSP();
        }

        void CodeGenerator::AssemblePopArgumentsAdaptorFrame(Register args_reg,
            Register scratch1,
            Register scratch2,
            Register scratch3)
        {
            DCHECK(!AreAliased(args_reg, scratch1, scratch2, scratch3));
            Label done;

            // Check if current frame is an arguments adaptor frame.
            __ LoadP(scratch1, MemOperand(fp, StandardFrameConstants::kContextOffset));
            __ CmpP(scratch1,
                Operand(StackFrame::TypeToMarker(StackFrame::ARGUMENTS_ADAPTOR)));
            __ bne(&done);

            // Load arguments count from current arguments adaptor frame (note, it
            // does not include receiver).
            Register caller_args_count_reg = scratch1;
            __ LoadP(caller_args_count_reg,
                MemOperand(fp, ArgumentsAdaptorFrameConstants::kLengthOffset));
            __ SmiUntag(caller_args_count_reg);

            ParameterCount callee_args_count(args_reg);
            __ PrepareForTailCall(callee_args_count, caller_args_count_reg, scratch2,
                scratch3);
            __ bind(&done);
        }

        namespace {

            void FlushPendingPushRegisters(TurboAssembler* tasm,
                FrameAccessState* frame_access_state,
                ZoneVector<Register>* pending_pushes)
            {
                switch (pending_pushes->size()) {
                case 0:
                    break;
                case 1:
                    tasm->Push((*pending_pushes)[0]);
                    break;
                case 2:
                    tasm->Push((*pending_pushes)[0], (*pending_pushes)[1]);
                    break;
                case 3:
                    tasm->Push((*pending_pushes)[0], (*pending_pushes)[1],
                        (*pending_pushes)[2]);
                    break;
                default:
                    UNREACHABLE();
                    break;
                }
                frame_access_state->IncreaseSPDelta(pending_pushes->size());
                pending_pushes->clear();
            }

            void AdjustStackPointerForTailCall(
                TurboAssembler* tasm, FrameAccessState* state, int new_slot_above_sp,
                ZoneVector<Register>* pending_pushes = nullptr,
                bool allow_shrinkage = true)
            {
                int current_sp_offset = state->GetSPToFPSlotCount() + StandardFrameConstants::kFixedSlotCountAboveFp;
                int stack_slot_delta = new_slot_above_sp - current_sp_offset;
                if (stack_slot_delta > 0) {
                    if (pending_pushes != nullptr) {
                        FlushPendingPushRegisters(tasm, state, pending_pushes);
                    }
                    tasm->AddP(sp, sp, Operand(-stack_slot_delta * kSystemPointerSize));
                    state->IncreaseSPDelta(stack_slot_delta);
                } else if (allow_shrinkage && stack_slot_delta < 0) {
                    if (pending_pushes != nullptr) {
                        FlushPendingPushRegisters(tasm, state, pending_pushes);
                    }
                    tasm->AddP(sp, sp, Operand(-stack_slot_delta * kSystemPointerSize));
                    state->IncreaseSPDelta(stack_slot_delta);
                }
            }

            void EmitWordLoadPoisoningIfNeeded(CodeGenerator* codegen, Instruction* instr,
                S390OperandConverter& i)
            {
                const MemoryAccessMode access_mode = static_cast<MemoryAccessMode>(MiscField::decode(instr->opcode()));
                if (access_mode == kMemoryAccessPoisoned) {
                    Register value = i.OutputRegister();
                    codegen->tasm()->AndP(value, kSpeculationPoisonRegister);
                }
            }

        } // namespace

        void CodeGenerator::AssembleTailCallBeforeGap(Instruction* instr,
            int first_unused_stack_slot)
        {
            ZoneVector<MoveOperands*> pushes(zone());
            GetPushCompatibleMoves(instr, kRegisterPush, &pushes);

            if (!pushes.empty() && (LocationOperand::cast(pushes.back()->destination()).index() + 1 == first_unused_stack_slot)) {
                S390OperandConverter g(this, instr);
                ZoneVector<Register> pending_pushes(zone());
                for (auto move : pushes) {
                    LocationOperand destination_location(
                        LocationOperand::cast(move->destination()));
                    InstructionOperand source(move->source());
                    AdjustStackPointerForTailCall(
                        tasm(), frame_access_state(),
                        destination_location.index() - pending_pushes.size(),
                        &pending_pushes);
                    // Pushes of non-register data types are not supported.
                    DCHECK(source.IsRegister());
                    LocationOperand source_location(LocationOperand::cast(source));
                    pending_pushes.push_back(source_location.GetRegister());
                    // TODO(arm): We can push more than 3 registers at once. Add support in
                    // the macro-assembler for pushing a list of registers.
                    if (pending_pushes.size() == 3) {
                        FlushPendingPushRegisters(tasm(), frame_access_state(),
                            &pending_pushes);
                    }
                    move->Eliminate();
                }
                FlushPendingPushRegisters(tasm(), frame_access_state(), &pending_pushes);
            }
            AdjustStackPointerForTailCall(tasm(), frame_access_state(),
                first_unused_stack_slot, nullptr, false);
        }

        void CodeGenerator::AssembleTailCallAfterGap(Instruction* instr,
            int first_unused_stack_slot)
        {
            AdjustStackPointerForTailCall(tasm(), frame_access_state(),
                first_unused_stack_slot);
        }

        // Check that {kJavaScriptCallCodeStartRegister} is correct.
        void CodeGenerator::AssembleCodeStartRegisterCheck()
        {
            Register scratch = r1;
            __ ComputeCodeStartAddress(scratch);
            __ CmpP(scratch, kJavaScriptCallCodeStartRegister);
            __ Assert(eq, AbortReason::kWrongFunctionCodeStart);
        }

        // Check if the code object is marked for deoptimization. If it is, then it
        // jumps to the CompileLazyDeoptimizedCode builtin. In order to do this we need
        // to:
        //    1. read from memory the word that contains that bit, which can be found in
        //       the flags in the referenced {CodeDataContainer} object;
        //    2. test kMarkedForDeoptimizationBit in those flags; and
        //    3. if it is not zero then it jumps to the builtin.
        void CodeGenerator::BailoutIfDeoptimized()
        {
            if (FLAG_debug_code) {
                // Check that {kJavaScriptCallCodeStartRegister} is correct.
                __ ComputeCodeStartAddress(ip);
                __ CmpP(ip, kJavaScriptCallCodeStartRegister);
                __ Assert(eq, AbortReason::kWrongFunctionCodeStart);
            }

            int offset = Code::kCodeDataContainerOffset - Code::kHeaderSize;
            __ LoadP(ip, MemOperand(kJavaScriptCallCodeStartRegister, offset));
            __ LoadW(ip,
                FieldMemOperand(ip, CodeDataContainer::kKindSpecificFlagsOffset));
            __ TestBit(ip, Code::kMarkedForDeoptimizationBit);
            __ Jump(BUILTIN_CODE(isolate(), CompileLazyDeoptimizedCode),
                RelocInfo::CODE_TARGET, ne);
        }

        void CodeGenerator::GenerateSpeculationPoisonFromCodeStartRegister()
        {
            Register scratch = r1;

            __ ComputeCodeStartAddress(scratch);

            // Calculate a mask which has all bits set in the normal case, but has all
            // bits cleared if we are speculatively executing the wrong PC.
            __ LoadImmP(kSpeculationPoisonRegister, Operand::Zero());
            __ LoadImmP(r0, Operand(-1));
            __ CmpP(kJavaScriptCallCodeStartRegister, scratch);
            __ LoadOnConditionP(eq, kSpeculationPoisonRegister, r0);
        }

        void CodeGenerator::AssembleRegisterArgumentPoisoning()
        {
            __ AndP(kJSFunctionRegister, kJSFunctionRegister, kSpeculationPoisonRegister);
            __ AndP(kContextRegister, kContextRegister, kSpeculationPoisonRegister);
            __ AndP(sp, sp, kSpeculationPoisonRegister);
        }

        // Assembles an instruction after register allocation, producing machine code.
        CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
            Instruction* instr)
        {
            S390OperandConverter i(this, instr);
            ArchOpcode opcode = ArchOpcodeField::decode(instr->opcode());

            switch (opcode) {
            case kArchComment:
#ifdef V8_TARGET_ARCH_S390X
                __ RecordComment(reinterpret_cast<const char*>(i.InputInt64(0)));
#else
                __ RecordComment(reinterpret_cast<const char*>(i.InputInt32(0)));
#endif
                break;
            case kArchCallCodeObject: {
                if (HasRegisterInput(instr, 0)) {
                    Register reg = i.InputRegister(0);
                    DCHECK_IMPLIES(
                        HasCallDescriptorFlag(instr, CallDescriptor::kFixedTargetRegister),
                        reg == kJavaScriptCallCodeStartRegister);
                    __ CallCodeObject(reg);
                } else {
                    __ Call(i.InputCode(0), RelocInfo::CODE_TARGET);
                }
                RecordCallPosition(instr);
                frame_access_state()->ClearSPDelta();
                break;
            }
            case kArchCallBuiltinPointer: {
                DCHECK(!instr->InputAt(0)->IsImmediate());
                Register builtin_pointer = i.InputRegister(0);
                __ CallBuiltinPointer(builtin_pointer);
                RecordCallPosition(instr);
                frame_access_state()->ClearSPDelta();
                break;
            }
            case kArchCallWasmFunction: {
                // We must not share code targets for calls to builtins for wasm code, as
                // they might need to be patched individually.
                if (instr->InputAt(0)->IsImmediate()) {
                    Constant constant = i.ToConstant(instr->InputAt(0));
#ifdef V8_TARGET_ARCH_S390X
                    Address wasm_code = static_cast<Address>(constant.ToInt64());
#else
                    Address wasm_code = static_cast<Address>(constant.ToInt32());
#endif
                    __ Call(wasm_code, constant.rmode());
                } else {
                    __ Call(i.InputRegister(0));
                }
                RecordCallPosition(instr);
                frame_access_state()->ClearSPDelta();
                break;
            }
            case kArchTailCallCodeObjectFromJSFunction:
            case kArchTailCallCodeObject: {
                if (opcode == kArchTailCallCodeObjectFromJSFunction) {
                    AssemblePopArgumentsAdaptorFrame(kJavaScriptCallArgCountRegister,
                        i.TempRegister(0), i.TempRegister(1),
                        i.TempRegister(2));
                }
                if (HasRegisterInput(instr, 0)) {
                    Register reg = i.InputRegister(0);
                    DCHECK_IMPLIES(
                        HasCallDescriptorFlag(instr, CallDescriptor::kFixedTargetRegister),
                        reg == kJavaScriptCallCodeStartRegister);
                    __ JumpCodeObject(reg);
                } else {
                    // We cannot use the constant pool to load the target since
                    // we've already restored the caller's frame.
                    ConstantPoolUnavailableScope constant_pool_unavailable(tasm());
                    __ Jump(i.InputCode(0), RelocInfo::CODE_TARGET);
                }
                frame_access_state()->ClearSPDelta();
                frame_access_state()->SetFrameAccessToDefault();
                break;
            }
            case kArchTailCallWasm: {
                // We must not share code targets for calls to builtins for wasm code, as
                // they might need to be patched individually.
                if (instr->InputAt(0)->IsImmediate()) {
                    Constant constant = i.ToConstant(instr->InputAt(0));
#ifdef V8_TARGET_ARCH_S390X
                    Address wasm_code = static_cast<Address>(constant.ToInt64());
#else
                    Address wasm_code = static_cast<Address>(constant.ToInt32());
#endif
                    __ Jump(wasm_code, constant.rmode());
                } else {
                    __ Jump(i.InputRegister(0));
                }
                frame_access_state()->ClearSPDelta();
                frame_access_state()->SetFrameAccessToDefault();
                break;
            }
            case kArchTailCallAddress: {
                CHECK(!instr->InputAt(0)->IsImmediate());
                Register reg = i.InputRegister(0);
                DCHECK_IMPLIES(
                    HasCallDescriptorFlag(instr, CallDescriptor::kFixedTargetRegister),
                    reg == kJavaScriptCallCodeStartRegister);
                __ Jump(reg);
                frame_access_state()->ClearSPDelta();
                frame_access_state()->SetFrameAccessToDefault();
                break;
            }
            case kArchCallJSFunction: {
                Register func = i.InputRegister(0);
                if (FLAG_debug_code) {
                    // Check the function's context matches the context argument.
                    __ LoadP(kScratchReg,
                        FieldMemOperand(func, JSFunction::kContextOffset));
                    __ CmpP(cp, kScratchReg);
                    __ Assert(eq, AbortReason::kWrongFunctionContext);
                }
                static_assert(kJavaScriptCallCodeStartRegister == r4, "ABI mismatch");
                __ LoadP(r4, FieldMemOperand(func, JSFunction::kCodeOffset));
                __ CallCodeObject(r4);
                RecordCallPosition(instr);
                frame_access_state()->ClearSPDelta();
                break;
            }
            case kArchPrepareCallCFunction: {
                int const num_parameters = MiscField::decode(instr->opcode());
                __ PrepareCallCFunction(num_parameters, kScratchReg);
                // Frame alignment requires using FP-relative frame addressing.
                frame_access_state()->SetFrameAccessToFP();
                break;
            }
            case kArchSaveCallerRegisters: {
                fp_mode_ = static_cast<SaveFPRegsMode>(MiscField::decode(instr->opcode()));
                DCHECK(fp_mode_ == kDontSaveFPRegs || fp_mode_ == kSaveFPRegs);
                // kReturnRegister0 should have been saved before entering the stub.
                int bytes = __ PushCallerSaved(fp_mode_, kReturnRegister0);
                DCHECK(IsAligned(bytes, kSystemPointerSize));
                DCHECK_EQ(0, frame_access_state()->sp_delta());
                frame_access_state()->IncreaseSPDelta(bytes / kSystemPointerSize);
                DCHECK(!caller_registers_saved_);
                caller_registers_saved_ = true;
                break;
            }
            case kArchRestoreCallerRegisters: {
                DCHECK(fp_mode_ == static_cast<SaveFPRegsMode>(MiscField::decode(instr->opcode())));
                DCHECK(fp_mode_ == kDontSaveFPRegs || fp_mode_ == kSaveFPRegs);
                // Don't overwrite the returned value.
                int bytes = __ PopCallerSaved(fp_mode_, kReturnRegister0);
                frame_access_state()->IncreaseSPDelta(-(bytes / kSystemPointerSize));
                DCHECK_EQ(0, frame_access_state()->sp_delta());
                DCHECK(caller_registers_saved_);
                caller_registers_saved_ = false;
                break;
            }
            case kArchPrepareTailCall:
                AssemblePrepareTailCall();
                break;
            case kArchCallCFunction: {
                int const num_parameters = MiscField::decode(instr->opcode());
                if (instr->InputAt(0)->IsImmediate()) {
                    ExternalReference ref = i.InputExternalReference(0);
                    __ CallCFunction(ref, num_parameters);
                } else {
                    Register func = i.InputRegister(0);
                    __ CallCFunction(func, num_parameters);
                }
                frame_access_state()->SetFrameAccessToDefault();
                // Ideally, we should decrement SP delta to match the change of stack
                // pointer in CallCFunction. However, for certain architectures (e.g.
                // ARM), there may be more strict alignment requirement, causing old SP
                // to be saved on the stack. In those cases, we can not calculate the SP
                // delta statically.
                frame_access_state()->ClearSPDelta();
                if (caller_registers_saved_) {
                    // Need to re-sync SP delta introduced in kArchSaveCallerRegisters.
                    // Here, we assume the sequence to be:
                    //   kArchSaveCallerRegisters;
                    //   kArchCallCFunction;
                    //   kArchRestoreCallerRegisters;
                    int bytes = __ RequiredStackSizeForCallerSaved(fp_mode_, kReturnRegister0);
                    frame_access_state()->IncreaseSPDelta(bytes / kSystemPointerSize);
                }
                break;
            }
            case kArchJmp:
                AssembleArchJump(i.InputRpo(0));
                break;
            case kArchBinarySearchSwitch:
                AssembleArchBinarySearchSwitch(instr);
                break;
            case kArchLookupSwitch:
                AssembleArchLookupSwitch(instr);
                break;
            case kArchTableSwitch:
                AssembleArchTableSwitch(instr);
                break;
            case kArchDebugAbort:
                DCHECK(i.InputRegister(0) == r3);
                if (!frame_access_state()->has_frame()) {
                    // We don't actually want to generate a pile of code for this, so just
                    // claim there is a stack frame, without generating one.
                    FrameScope scope(tasm(), StackFrame::NONE);
                    __ Call(isolate()->builtins()->builtin_handle(Builtins::kAbortJS),
                        RelocInfo::CODE_TARGET);
                } else {
                    __ Call(isolate()->builtins()->builtin_handle(Builtins::kAbortJS),
                        RelocInfo::CODE_TARGET);
                }
                __ stop("kArchDebugAbort");
                break;
            case kArchDebugBreak:
                __ stop("kArchDebugBreak");
                break;
            case kArchNop:
            case kArchThrowTerminator:
                // don't emit code for nops.
                break;
            case kArchDeoptimize: {
                int deopt_state_id = BuildTranslation(instr, -1, 0, OutputFrameStateCombine::Ignore());
                CodeGenResult result = AssembleDeoptimizerCall(deopt_state_id, current_source_position_);
                if (result != kSuccess)
                    return result;
                break;
            }
            case kArchRet:
                AssembleReturn(instr->InputAt(0));
                break;
            case kArchStackPointer:
                __ LoadRR(i.OutputRegister(), sp);
                break;
            case kArchFramePointer:
                __ LoadRR(i.OutputRegister(), fp);
                break;
            case kArchParentFramePointer:
                if (frame_access_state()->has_frame()) {
                    __ LoadP(i.OutputRegister(), MemOperand(fp, 0));
                } else {
                    __ LoadRR(i.OutputRegister(), fp);
                }
                break;
            case kArchTruncateDoubleToI:
                __ TruncateDoubleToI(isolate(), zone(), i.OutputRegister(),
                    i.InputDoubleRegister(0), DetermineStubCallMode());
                break;
            case kArchStoreWithWriteBarrier: {
                RecordWriteMode mode = static_cast<RecordWriteMode>(MiscField::decode(instr->opcode()));
                Register object = i.InputRegister(0);
                Register value = i.InputRegister(2);
                Register scratch0 = i.TempRegister(0);
                Register scratch1 = i.TempRegister(1);
                OutOfLineRecordWrite* ool;

                AddressingMode addressing_mode = AddressingModeField::decode(instr->opcode());
                if (addressing_mode == kMode_MRI) {
                    int32_t offset = i.InputInt32(1);
                    ool = new (zone())
                        OutOfLineRecordWrite(this, object, offset, value, scratch0,
                            scratch1, mode, DetermineStubCallMode());
                    __ StoreP(value, MemOperand(object, offset));
                } else {
                    DCHECK_EQ(kMode_MRR, addressing_mode);
                    Register offset(i.InputRegister(1));
                    ool = new (zone())
                        OutOfLineRecordWrite(this, object, offset, value, scratch0,
                            scratch1, mode, DetermineStubCallMode());
                    __ StoreP(value, MemOperand(object, offset));
                }
                __ CheckPageFlag(object, scratch0,
                    MemoryChunk::kPointersFromHereAreInterestingMask, ne,
                    ool->entry());
                __ bind(ool->exit());
                break;
            }
            case kArchStackSlot: {
                FrameOffset offset = frame_access_state()->GetFrameOffset(i.InputInt32(0));
                __ AddP(i.OutputRegister(), offset.from_stack_pointer() ? sp : fp,
                    Operand(offset.offset()));
                break;
            }
            case kArchWordPoisonOnSpeculation:
                DCHECK_EQ(i.OutputRegister(), i.InputRegister(0));
                __ AndP(i.InputRegister(0), kSpeculationPoisonRegister);
                break;
            case kS390_Peek: {
                // The incoming value is 0-based, but we need a 1-based value.
                int reverse_slot = i.InputInt32(0) + 1;
                int offset = FrameSlotToFPOffset(frame()->GetTotalFrameSlotCount() - reverse_slot);
                if (instr->OutputAt(0)->IsFPRegister()) {
                    LocationOperand* op = LocationOperand::cast(instr->OutputAt(0));
                    if (op->representation() == MachineRepresentation::kFloat64) {
                        __ LoadDouble(i.OutputDoubleRegister(), MemOperand(fp, offset));
                    } else {
                        DCHECK_EQ(MachineRepresentation::kFloat32, op->representation());
                        __ LoadFloat32(i.OutputFloatRegister(), MemOperand(fp, offset));
                    }
                } else {
                    __ LoadP(i.OutputRegister(), MemOperand(fp, offset));
                }
                break;
            }
            case kS390_Abs32:
                // TODO(john.yan): zero-ext
                __ lpr(i.OutputRegister(0), i.InputRegister(0));
                break;
            case kS390_Abs64:
                __ lpgr(i.OutputRegister(0), i.InputRegister(0));
                break;
            case kS390_And32:
                // zero-ext
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(nrk), RM32Instr(And), RIInstr(nilf));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(nr), RM32Instr(And), RIInstr(nilf));
                }
                break;
            case kS390_And64:
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN_OP(RRRInstr(ngrk), RM64Instr(ng), nullInstr);
                } else {
                    ASSEMBLE_BIN_OP(RRInstr(ngr), RM64Instr(ng), nullInstr);
                }
                break;
            case kS390_Or32:
                // zero-ext
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(ork), RM32Instr(Or), RIInstr(oilf));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(or_z), RM32Instr(Or), RIInstr(oilf));
                }
                break;
            case kS390_Or64:
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN_OP(RRRInstr(ogrk), RM64Instr(og), nullInstr);
                } else {
                    ASSEMBLE_BIN_OP(RRInstr(ogr), RM64Instr(og), nullInstr);
                }
                break;
            case kS390_Xor32:
                // zero-ext
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(xrk), RM32Instr(Xor), RIInstr(xilf));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(xr), RM32Instr(Xor), RIInstr(xilf));
                }
                break;
            case kS390_Xor64:
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN_OP(RRRInstr(xgrk), RM64Instr(xg), nullInstr);
                } else {
                    ASSEMBLE_BIN_OP(RRInstr(xgr), RM64Instr(xg), nullInstr);
                }
                break;
            case kS390_ShiftLeft32:
                // zero-ext
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(ShiftLeft), nullInstr, RRIInstr(ShiftLeft));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(sll), nullInstr, RIInstr(sll));
                }
                break;
            case kS390_ShiftLeft64:
                ASSEMBLE_BIN_OP(RRRInstr(sllg), nullInstr, RRIInstr(sllg));
                break;
            case kS390_ShiftRight32:
                // zero-ext
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(srlk), nullInstr, RRIInstr(srlk));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(srl), nullInstr, RIInstr(srl));
                }
                break;
            case kS390_ShiftRight64:
                ASSEMBLE_BIN_OP(RRRInstr(srlg), nullInstr, RRIInstr(srlg));
                break;
            case kS390_ShiftRightArith32:
                // zero-ext
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(srak), nullInstr, RRIInstr(srak));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(sra), nullInstr, RIInstr(sra));
                }
                break;
            case kS390_ShiftRightArith64:
                ASSEMBLE_BIN_OP(RRRInstr(srag), nullInstr, RRIInstr(srag));
                break;
#if !V8_TARGET_ARCH_S390X
            case kS390_AddPair:
                // i.InputRegister(0) ... left low word.
                // i.InputRegister(1) ... left high word.
                // i.InputRegister(2) ... right low word.
                // i.InputRegister(3) ... right high word.
                __ AddLogical32(i.OutputRegister(0), i.InputRegister(0),
                    i.InputRegister(2));
                __ AddLogicalWithCarry32(i.OutputRegister(1), i.InputRegister(1),
                    i.InputRegister(3));
                break;
            case kS390_SubPair:
                // i.InputRegister(0) ... left low word.
                // i.InputRegister(1) ... left high word.
                // i.InputRegister(2) ... right low word.
                // i.InputRegister(3) ... right high word.
                __ SubLogical32(i.OutputRegister(0), i.InputRegister(0),
                    i.InputRegister(2));
                __ SubLogicalWithBorrow32(i.OutputRegister(1), i.InputRegister(1),
                    i.InputRegister(3));
                break;
            case kS390_MulPair:
                // i.InputRegister(0) ... left low word.
                // i.InputRegister(1) ... left high word.
                // i.InputRegister(2) ... right low word.
                // i.InputRegister(3) ... right high word.
                __ sllg(r0, i.InputRegister(1), Operand(32));
                __ sllg(r1, i.InputRegister(3), Operand(32));
                __ lr(r0, i.InputRegister(0));
                __ lr(r1, i.InputRegister(2));
                __ msgr(r1, r0);
                __ lr(i.OutputRegister(0), r1);
                __ srag(i.OutputRegister(1), r1, Operand(32));
                break;
            case kS390_ShiftLeftPair: {
                Register second_output = instr->OutputCount() >= 2 ? i.OutputRegister(1) : i.TempRegister(0);
                if (instr->InputAt(2)->IsImmediate()) {
                    __ ShiftLeftPair(i.OutputRegister(0), second_output, i.InputRegister(0),
                        i.InputRegister(1), i.InputInt32(2));
                } else {
                    __ ShiftLeftPair(i.OutputRegister(0), second_output, i.InputRegister(0),
                        i.InputRegister(1), kScratchReg, i.InputRegister(2));
                }
                break;
            }
            case kS390_ShiftRightPair: {
                Register second_output = instr->OutputCount() >= 2 ? i.OutputRegister(1) : i.TempRegister(0);
                if (instr->InputAt(2)->IsImmediate()) {
                    __ ShiftRightPair(i.OutputRegister(0), second_output,
                        i.InputRegister(0), i.InputRegister(1),
                        i.InputInt32(2));
                } else {
                    __ ShiftRightPair(i.OutputRegister(0), second_output,
                        i.InputRegister(0), i.InputRegister(1), kScratchReg,
                        i.InputRegister(2));
                }
                break;
            }
            case kS390_ShiftRightArithPair: {
                Register second_output = instr->OutputCount() >= 2 ? i.OutputRegister(1) : i.TempRegister(0);
                if (instr->InputAt(2)->IsImmediate()) {
                    __ ShiftRightArithPair(i.OutputRegister(0), second_output,
                        i.InputRegister(0), i.InputRegister(1),
                        i.InputInt32(2));
                } else {
                    __ ShiftRightArithPair(i.OutputRegister(0), second_output,
                        i.InputRegister(0), i.InputRegister(1),
                        kScratchReg, i.InputRegister(2));
                }
                break;
            }
#endif
            case kS390_RotRight32: {
                // zero-ext
                if (HasRegisterInput(instr, 1)) {
                    __ LoadComplementRR(kScratchReg, i.InputRegister(1));
                    __ rll(i.OutputRegister(), i.InputRegister(0), kScratchReg);
                } else {
                    __ rll(i.OutputRegister(), i.InputRegister(0),
                        Operand(32 - i.InputInt32(1)));
                }
                CHECK_AND_ZERO_EXT_OUTPUT(2);
                break;
            }
            case kS390_RotRight64:
                if (HasRegisterInput(instr, 1)) {
                    __ lcgr(kScratchReg, i.InputRegister(1));
                    __ rllg(i.OutputRegister(), i.InputRegister(0), kScratchReg);
                } else {
                    DCHECK(HasImmediateInput(instr, 1));
                    __ rllg(i.OutputRegister(), i.InputRegister(0),
                        Operand(64 - i.InputInt32(1)));
                }
                break;
            // TODO(john.yan): clean up kS390_RotLeftAnd...
            case kS390_RotLeftAndClear64:
                if (CpuFeatures::IsSupported(GENERAL_INSTR_EXT)) {
                    int shiftAmount = i.InputInt32(1);
                    int endBit = 63 - shiftAmount;
                    int startBit = 63 - i.InputInt32(2);
                    __ RotateInsertSelectBits(i.OutputRegister(), i.InputRegister(0),
                        Operand(startBit), Operand(endBit),
                        Operand(shiftAmount), true);
                } else {
                    int shiftAmount = i.InputInt32(1);
                    int clearBit = 63 - i.InputInt32(2);
                    __ rllg(i.OutputRegister(), i.InputRegister(0), Operand(shiftAmount));
                    __ sllg(i.OutputRegister(), i.OutputRegister(), Operand(clearBit));
                    __ srlg(i.OutputRegister(), i.OutputRegister(),
                        Operand(clearBit + shiftAmount));
                    __ sllg(i.OutputRegister(), i.OutputRegister(), Operand(shiftAmount));
                }
                break;
            case kS390_RotLeftAndClearLeft64:
                if (CpuFeatures::IsSupported(GENERAL_INSTR_EXT)) {
                    int shiftAmount = i.InputInt32(1);
                    int endBit = 63;
                    int startBit = 63 - i.InputInt32(2);
                    __ RotateInsertSelectBits(i.OutputRegister(), i.InputRegister(0),
                        Operand(startBit), Operand(endBit),
                        Operand(shiftAmount), true);
                } else {
                    int shiftAmount = i.InputInt32(1);
                    int clearBit = 63 - i.InputInt32(2);
                    __ rllg(i.OutputRegister(), i.InputRegister(0), Operand(shiftAmount));
                    __ sllg(i.OutputRegister(), i.OutputRegister(), Operand(clearBit));
                    __ srlg(i.OutputRegister(), i.OutputRegister(), Operand(clearBit));
                }
                break;
            case kS390_RotLeftAndClearRight64:
                if (CpuFeatures::IsSupported(GENERAL_INSTR_EXT)) {
                    int shiftAmount = i.InputInt32(1);
                    int endBit = 63 - i.InputInt32(2);
                    int startBit = 0;
                    __ RotateInsertSelectBits(i.OutputRegister(), i.InputRegister(0),
                        Operand(startBit), Operand(endBit),
                        Operand(shiftAmount), true);
                } else {
                    int shiftAmount = i.InputInt32(1);
                    int clearBit = i.InputInt32(2);
                    __ rllg(i.OutputRegister(), i.InputRegister(0), Operand(shiftAmount));
                    __ srlg(i.OutputRegister(), i.OutputRegister(), Operand(clearBit));
                    __ sllg(i.OutputRegister(), i.OutputRegister(), Operand(clearBit));
                }
                break;
            case kS390_Add32: {
                // zero-ext
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(ark), RM32Instr(Add32), RRIInstr(Add32));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(ar), RM32Instr(Add32), RIInstr(Add32));
                }
                break;
            }
            case kS390_Add64:
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN_OP(RRRInstr(agrk), RM64Instr(ag), RRIInstr(AddP));
                } else {
                    ASSEMBLE_BIN_OP(RRInstr(agr), RM64Instr(ag), RIInstr(agfi));
                }
                break;
            case kS390_AddFloat:
                ASSEMBLE_BIN_OP(DDInstr(aebr), DMTInstr(AddFloat32), nullInstr);
                break;
            case kS390_AddDouble:
                ASSEMBLE_BIN_OP(DDInstr(adbr), DMTInstr(AddFloat64), nullInstr);
                break;
            case kS390_Sub32:
                // zero-ext
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(srk), RM32Instr(Sub32), RRIInstr(Sub32));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(sr), RM32Instr(Sub32), RIInstr(Sub32));
                }
                break;
            case kS390_Sub64:
                if (CpuFeatures::IsSupported(DISTINCT_OPS)) {
                    ASSEMBLE_BIN_OP(RRRInstr(sgrk), RM64Instr(sg), RRIInstr(SubP));
                } else {
                    ASSEMBLE_BIN_OP(RRInstr(sgr), RM64Instr(sg), RIInstr(SubP));
                }
                break;
            case kS390_SubFloat:
                ASSEMBLE_BIN_OP(DDInstr(sebr), DMTInstr(SubFloat32), nullInstr);
                break;
            case kS390_SubDouble:
                ASSEMBLE_BIN_OP(DDInstr(sdbr), DMTInstr(SubFloat64), nullInstr);
                break;
            case kS390_Mul32:
                // zero-ext
                if (CpuFeatures::IsSupported(MISC_INSTR_EXT2)) {
                    ASSEMBLE_BIN32_OP(RRRInstr(msrkc), RM32Instr(msc), RIInstr(Mul32));
                } else {
                    ASSEMBLE_BIN32_OP(RRInstr(Mul32), RM32Instr(Mul32), RIInstr(Mul32));
                }
                break;
            case kS390_Mul32WithOverflow:
                // zero-ext
                ASSEMBLE_BIN32_OP(RRRInstr(Mul32WithOverflowIfCCUnequal),
                    RRM32Instr(Mul32WithOverflowIfCCUnequal),
                    RRIInstr(Mul32WithOverflowIfCCUnequal));
                break;
            case kS390_Mul64:
                ASSEMBLE_BIN_OP(RRInstr(Mul64), RM64Instr(Mul64), RIInstr(Mul64));
                break;
            case kS390_MulHigh32:
                // zero-ext
                ASSEMBLE_BIN_OP(RRRInstr(MulHigh32), RRM32Instr(MulHigh32),
                    RRIInstr(MulHigh32));
                break;
            case kS390_MulHighU32:
                // zero-ext
                ASSEMBLE_BIN_OP(RRRInstr(MulHighU32), RRM32Instr(MulHighU32),
                    RRIInstr(MulHighU32));
                break;
            case kS390_MulFloat:
                ASSEMBLE_BIN_OP(DDInstr(meebr), DMTInstr(MulFloat32), nullInstr);
                break;
            case kS390_MulDouble:
                ASSEMBLE_BIN_OP(DDInstr(mdbr), DMTInstr(MulFloat64), nullInstr);
                break;
            case kS390_Div64:
                ASSEMBLE_BIN_OP(RRRInstr(Div64), RRM64Instr(Div64), nullInstr);
                break;
            case kS390_Div32: {
                // zero-ext
                ASSEMBLE_BIN_OP(RRRInstr(Div32), RRM32Instr(Div32), nullInstr);
                break;
            }
            case kS390_DivU64:
                ASSEMBLE_BIN_OP(RRRInstr(DivU64), RRM64Instr(DivU64), nullInstr);
                break;
            case kS390_DivU32: {
                // zero-ext
                ASSEMBLE_BIN_OP(RRRInstr(DivU32), RRM32Instr(DivU32), nullInstr);
                break;
            }
            case kS390_DivFloat:
                ASSEMBLE_BIN_OP(DDInstr(debr), DMTInstr(DivFloat32), nullInstr);
                break;
            case kS390_DivDouble:
                ASSEMBLE_BIN_OP(DDInstr(ddbr), DMTInstr(DivFloat64), nullInstr);
                break;
            case kS390_Mod32:
                // zero-ext
                ASSEMBLE_BIN_OP(RRRInstr(Mod32), RRM32Instr(Mod32), nullInstr);
                break;
            case kS390_ModU32:
                // zero-ext
                ASSEMBLE_BIN_OP(RRRInstr(ModU32), RRM32Instr(ModU32), nullInstr);
                break;
            case kS390_Mod64:
                ASSEMBLE_BIN_OP(RRRInstr(Mod64), RRM64Instr(Mod64), nullInstr);
                break;
            case kS390_ModU64:
                ASSEMBLE_BIN_OP(RRRInstr(ModU64), RRM64Instr(ModU64), nullInstr);
                break;
            case kS390_AbsFloat:
                __ lpebr(i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_SqrtFloat:
                ASSEMBLE_UNARY_OP(D_DInstr(sqebr), nullInstr, nullInstr);
                break;
            case kS390_SqrtDouble:
                ASSEMBLE_UNARY_OP(D_DInstr(sqdbr), nullInstr, nullInstr);
                break;
            case kS390_FloorFloat:
                __ fiebra(v8::internal::Assembler::FIDBRA_ROUND_TOWARD_NEG_INF,
                    i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_CeilFloat:
                __ fiebra(v8::internal::Assembler::FIDBRA_ROUND_TOWARD_POS_INF,
                    i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_TruncateFloat:
                __ fiebra(v8::internal::Assembler::FIDBRA_ROUND_TOWARD_0,
                    i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            //  Double operations
            case kS390_ModDouble:
                ASSEMBLE_FLOAT_MODULO();
                break;
            case kIeee754Float64Acos:
                ASSEMBLE_IEEE754_UNOP(acos);
                break;
            case kIeee754Float64Acosh:
                ASSEMBLE_IEEE754_UNOP(acosh);
                break;
            case kIeee754Float64Asin:
                ASSEMBLE_IEEE754_UNOP(asin);
                break;
            case kIeee754Float64Asinh:
                ASSEMBLE_IEEE754_UNOP(asinh);
                break;
            case kIeee754Float64Atanh:
                ASSEMBLE_IEEE754_UNOP(atanh);
                break;
            case kIeee754Float64Atan:
                ASSEMBLE_IEEE754_UNOP(atan);
                break;
            case kIeee754Float64Atan2:
                ASSEMBLE_IEEE754_BINOP(atan2);
                break;
            case kIeee754Float64Tan:
                ASSEMBLE_IEEE754_UNOP(tan);
                break;
            case kIeee754Float64Tanh:
                ASSEMBLE_IEEE754_UNOP(tanh);
                break;
            case kIeee754Float64Cbrt:
                ASSEMBLE_IEEE754_UNOP(cbrt);
                break;
            case kIeee754Float64Sin:
                ASSEMBLE_IEEE754_UNOP(sin);
                break;
            case kIeee754Float64Sinh:
                ASSEMBLE_IEEE754_UNOP(sinh);
                break;
            case kIeee754Float64Cos:
                ASSEMBLE_IEEE754_UNOP(cos);
                break;
            case kIeee754Float64Cosh:
                ASSEMBLE_IEEE754_UNOP(cosh);
                break;
            case kIeee754Float64Exp:
                ASSEMBLE_IEEE754_UNOP(exp);
                break;
            case kIeee754Float64Expm1:
                ASSEMBLE_IEEE754_UNOP(expm1);
                break;
            case kIeee754Float64Log:
                ASSEMBLE_IEEE754_UNOP(log);
                break;
            case kIeee754Float64Log1p:
                ASSEMBLE_IEEE754_UNOP(log1p);
                break;
            case kIeee754Float64Log2:
                ASSEMBLE_IEEE754_UNOP(log2);
                break;
            case kIeee754Float64Log10:
                ASSEMBLE_IEEE754_UNOP(log10);
                break;
            case kIeee754Float64Pow:
                ASSEMBLE_IEEE754_BINOP(pow);
                break;
            case kS390_Neg32:
                __ lcr(i.OutputRegister(), i.InputRegister(0));
                CHECK_AND_ZERO_EXT_OUTPUT(1);
                break;
            case kS390_Neg64:
                __ lcgr(i.OutputRegister(), i.InputRegister(0));
                break;
            case kS390_MaxFloat:
                ASSEMBLE_FLOAT_MAX();
                break;
            case kS390_MaxDouble:
                ASSEMBLE_DOUBLE_MAX();
                break;
            case kS390_MinFloat:
                ASSEMBLE_FLOAT_MIN();
                break;
            case kS390_MinDouble:
                ASSEMBLE_DOUBLE_MIN();
                break;
            case kS390_AbsDouble:
                __ lpdbr(i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_FloorDouble:
                __ fidbra(v8::internal::Assembler::FIDBRA_ROUND_TOWARD_NEG_INF,
                    i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_CeilDouble:
                __ fidbra(v8::internal::Assembler::FIDBRA_ROUND_TOWARD_POS_INF,
                    i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_TruncateDouble:
                __ fidbra(v8::internal::Assembler::FIDBRA_ROUND_TOWARD_0,
                    i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_RoundDouble:
                __ fidbra(v8::internal::Assembler::FIDBRA_ROUND_TO_NEAREST_AWAY_FROM_0,
                    i.OutputDoubleRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_NegFloat:
                ASSEMBLE_UNARY_OP(D_DInstr(lcebr), nullInstr, nullInstr);
                break;
            case kS390_NegDouble:
                ASSEMBLE_UNARY_OP(D_DInstr(lcdbr), nullInstr, nullInstr);
                break;
            case kS390_Cntlz32: {
                __ llgfr(i.OutputRegister(), i.InputRegister(0));
                __ flogr(r0, i.OutputRegister());
                __ Add32(i.OutputRegister(), r0, Operand(-32));
                // No need to zero-ext b/c llgfr is done already
                break;
            }
#if V8_TARGET_ARCH_S390X
            case kS390_Cntlz64: {
                __ flogr(r0, i.InputRegister(0));
                __ LoadRR(i.OutputRegister(), r0);
                break;
            }
#endif
            case kS390_Popcnt32:
                __ Popcnt32(i.OutputRegister(), i.InputRegister(0));
                break;
#if V8_TARGET_ARCH_S390X
            case kS390_Popcnt64:
                __ Popcnt64(i.OutputRegister(), i.InputRegister(0));
                break;
#endif
            case kS390_Cmp32:
                ASSEMBLE_COMPARE32(Cmp32, CmpLogical32);
                break;
#if V8_TARGET_ARCH_S390X
            case kS390_Cmp64:
                ASSEMBLE_COMPARE(CmpP, CmpLogicalP);
                break;
#endif
            case kS390_CmpFloat:
                ASSEMBLE_FLOAT_COMPARE(cebr, ceb, ley);
                // __ cebr(i.InputDoubleRegister(0), i.InputDoubleRegister(1));
                break;
            case kS390_CmpDouble:
                ASSEMBLE_FLOAT_COMPARE(cdbr, cdb, ldy);
                // __ cdbr(i.InputDoubleRegister(0), i.InputDoubleRegister(1));
                break;
            case kS390_Tst32:
                if (HasRegisterInput(instr, 1)) {
                    __ And(r0, i.InputRegister(0), i.InputRegister(1));
                } else {
                    // detect tmlh/tmhl/tmhh case
                    Operand opnd = i.InputImmediate(1);
                    if (is_uint16(opnd.immediate())) {
                        __ tmll(i.InputRegister(0), opnd);
                    } else {
                        __ lr(r0, i.InputRegister(0));
                        __ nilf(r0, opnd);
                    }
                }
                break;
            case kS390_Tst64:
                if (HasRegisterInput(instr, 1)) {
                    __ AndP(r0, i.InputRegister(0), i.InputRegister(1));
                } else {
                    Operand opnd = i.InputImmediate(1);
                    if (is_uint16(opnd.immediate())) {
                        __ tmll(i.InputRegister(0), opnd);
                    } else {
                        __ AndP(r0, i.InputRegister(0), opnd);
                    }
                }
                break;
            case kS390_Float64SilenceNaN: {
                DoubleRegister value = i.InputDoubleRegister(0);
                DoubleRegister result = i.OutputDoubleRegister();
                __ CanonicalizeNaN(result, value);
                break;
            }
            case kS390_StackClaim: {
                int num_slots = i.InputInt32(0);
                __ lay(sp, MemOperand(sp, -num_slots * kSystemPointerSize));
                frame_access_state()->IncreaseSPDelta(num_slots);
                break;
            }
            case kS390_Push:
                if (instr->InputAt(0)->IsFPRegister()) {
                    LocationOperand* op = LocationOperand::cast(instr->InputAt(0));
                    if (op->representation() == MachineRepresentation::kFloat64) {
                        __ lay(sp, MemOperand(sp, -kDoubleSize));
                        __ StoreDouble(i.InputDoubleRegister(0), MemOperand(sp));
                        frame_access_state()->IncreaseSPDelta(kDoubleSize / kSystemPointerSize);
                    } else {
                        DCHECK_EQ(MachineRepresentation::kFloat32, op->representation());
                        __ lay(sp, MemOperand(sp, -kSystemPointerSize));
                        __ StoreFloat32(i.InputDoubleRegister(0), MemOperand(sp));
                        frame_access_state()->IncreaseSPDelta(1);
                    }
                } else {
                    __ Push(i.InputRegister(0));
                    frame_access_state()->IncreaseSPDelta(1);
                }
                break;
            case kS390_PushFrame: {
                int num_slots = i.InputInt32(1);
                __ lay(sp, MemOperand(sp, -num_slots * kSystemPointerSize));
                if (instr->InputAt(0)->IsFPRegister()) {
                    LocationOperand* op = LocationOperand::cast(instr->InputAt(0));
                    if (op->representation() == MachineRepresentation::kFloat64) {
                        __ StoreDouble(i.InputDoubleRegister(0), MemOperand(sp));
                    } else {
                        DCHECK_EQ(MachineRepresentation::kFloat32, op->representation());
                        __ StoreFloat32(i.InputDoubleRegister(0), MemOperand(sp));
                    }
                } else {
                    __ StoreP(i.InputRegister(0), MemOperand(sp));
                }
                break;
            }
            case kS390_StoreToStackSlot: {
                int slot = i.InputInt32(1);
                if (instr->InputAt(0)->IsFPRegister()) {
                    LocationOperand* op = LocationOperand::cast(instr->InputAt(0));
                    if (op->representation() == MachineRepresentation::kFloat64) {
                        __ StoreDouble(i.InputDoubleRegister(0),
                            MemOperand(sp, slot * kSystemPointerSize));
                    } else {
                        DCHECK_EQ(MachineRepresentation::kFloat32, op->representation());
                        __ StoreFloat32(i.InputDoubleRegister(0),
                            MemOperand(sp, slot * kSystemPointerSize));
                    }
                } else {
                    __ StoreP(i.InputRegister(0),
                        MemOperand(sp, slot * kSystemPointerSize));
                }
                break;
            }
            case kS390_SignExtendWord8ToInt32:
                __ lbr(i.OutputRegister(), i.InputRegister(0));
                CHECK_AND_ZERO_EXT_OUTPUT(1);
                break;
            case kS390_SignExtendWord16ToInt32:
                __ lhr(i.OutputRegister(), i.InputRegister(0));
                CHECK_AND_ZERO_EXT_OUTPUT(1);
                break;
            case kS390_SignExtendWord8ToInt64:
                __ lgbr(i.OutputRegister(), i.InputRegister(0));
                break;
            case kS390_SignExtendWord16ToInt64:
                __ lghr(i.OutputRegister(), i.InputRegister(0));
                break;
            case kS390_SignExtendWord32ToInt64:
                __ lgfr(i.OutputRegister(), i.InputRegister(0));
                break;
            case kS390_Uint32ToUint64:
                // Zero extend
                __ llgfr(i.OutputRegister(), i.InputRegister(0));
                break;
            case kS390_Int64ToInt32:
                // sign extend
                __ lgfr(i.OutputRegister(), i.InputRegister(0));
                break;
            // Convert Fixed to Floating Point
            case kS390_Int64ToFloat32:
                __ ConvertInt64ToFloat(i.OutputDoubleRegister(), i.InputRegister(0));
                break;
            case kS390_Int64ToDouble:
                __ ConvertInt64ToDouble(i.OutputDoubleRegister(), i.InputRegister(0));
                break;
            case kS390_Uint64ToFloat32:
                __ ConvertUnsignedInt64ToFloat(i.OutputDoubleRegister(),
                    i.InputRegister(0));
                break;
            case kS390_Uint64ToDouble:
                __ ConvertUnsignedInt64ToDouble(i.OutputDoubleRegister(),
                    i.InputRegister(0));
                break;
            case kS390_Int32ToFloat32:
                __ ConvertIntToFloat(i.OutputDoubleRegister(), i.InputRegister(0));
                break;
            case kS390_Int32ToDouble:
                __ ConvertIntToDouble(i.OutputDoubleRegister(), i.InputRegister(0));
                break;
            case kS390_Uint32ToFloat32:
                __ ConvertUnsignedIntToFloat(i.OutputDoubleRegister(),
                    i.InputRegister(0));
                break;
            case kS390_Uint32ToDouble:
                __ ConvertUnsignedIntToDouble(i.OutputDoubleRegister(),
                    i.InputRegister(0));
                break;
            case kS390_DoubleToInt32: {
                Label done;
                __ ConvertDoubleToInt32(i.OutputRegister(0), i.InputDoubleRegister(0),
                    kRoundToNearest);
                __ b(Condition(0xE), &done, Label::kNear); // normal case
                __ lghi(i.OutputRegister(0), Operand::Zero());
                __ bind(&done);
                break;
            }
            case kS390_DoubleToUint32: {
                Label done;
                __ ConvertDoubleToUnsignedInt32(i.OutputRegister(0),
                    i.InputDoubleRegister(0));
                __ b(Condition(0xE), &done, Label::kNear); // normal case
                __ lghi(i.OutputRegister(0), Operand::Zero());
                __ bind(&done);
                break;
            }
            case kS390_DoubleToInt64: {
                Label done;
                if (i.OutputCount() > 1) {
                    __ lghi(i.OutputRegister(1), Operand(1));
                }
                __ ConvertDoubleToInt64(i.OutputRegister(0), i.InputDoubleRegister(0));
                __ b(Condition(0xE), &done, Label::kNear); // normal case
                if (i.OutputCount() > 1) {
                    __ lghi(i.OutputRegister(1), Operand::Zero());
                } else {
                    __ lghi(i.OutputRegister(0), Operand::Zero());
                }
                __ bind(&done);
                break;
            }
            case kS390_DoubleToUint64: {
                Label done;
                if (i.OutputCount() > 1) {
                    __ lghi(i.OutputRegister(1), Operand(1));
                }
                __ ConvertDoubleToUnsignedInt64(i.OutputRegister(0),
                    i.InputDoubleRegister(0));
                __ b(Condition(0xE), &done, Label::kNear); // normal case
                if (i.OutputCount() > 1) {
                    __ lghi(i.OutputRegister(1), Operand::Zero());
                } else {
                    __ lghi(i.OutputRegister(0), Operand::Zero());
                }
                __ bind(&done);
                break;
            }
            case kS390_Float32ToInt32: {
                Label done;
                __ ConvertFloat32ToInt32(i.OutputRegister(0), i.InputDoubleRegister(0),
                    kRoundToZero);
                __ b(Condition(0xE), &done, Label::kNear); // normal case
                __ lghi(i.OutputRegister(0), Operand::Zero());
                __ bind(&done);
                break;
            }
            case kS390_Float32ToUint32: {
                Label done;
                __ ConvertFloat32ToUnsignedInt32(i.OutputRegister(0),
                    i.InputDoubleRegister(0));
                __ b(Condition(0xE), &done, Label::kNear); // normal case
                __ lghi(i.OutputRegister(0), Operand::Zero());
                __ bind(&done);
                break;
            }
            case kS390_Float32ToUint64: {
                Label done;
                if (i.OutputCount() > 1) {
                    __ lghi(i.OutputRegister(1), Operand(1));
                }
                __ ConvertFloat32ToUnsignedInt64(i.OutputRegister(0),
                    i.InputDoubleRegister(0));
                __ b(Condition(0xE), &done, Label::kNear); // normal case
                if (i.OutputCount() > 1) {
                    __ lghi(i.OutputRegister(1), Operand::Zero());
                } else {
                    __ lghi(i.OutputRegister(0), Operand::Zero());
                }
                __ bind(&done);
                break;
            }
            case kS390_Float32ToInt64: {
                Label done;
                if (i.OutputCount() > 1) {
                    __ lghi(i.OutputRegister(1), Operand(1));
                }
                __ ConvertFloat32ToInt64(i.OutputRegister(0), i.InputDoubleRegister(0));
                __ b(Condition(0xE), &done, Label::kNear); // normal case
                if (i.OutputCount() > 1) {
                    __ lghi(i.OutputRegister(1), Operand::Zero());
                } else {
                    __ lghi(i.OutputRegister(0), Operand::Zero());
                }
                __ bind(&done);
                break;
            }
            case kS390_DoubleToFloat32:
                ASSEMBLE_UNARY_OP(D_DInstr(ledbr), nullInstr, nullInstr);
                break;
            case kS390_Float32ToDouble:
                ASSEMBLE_UNARY_OP(D_DInstr(ldebr), D_MTInstr(LoadFloat32ToDouble),
                    nullInstr);
                break;
            case kS390_DoubleExtractLowWord32:
                __ lgdr(i.OutputRegister(), i.InputDoubleRegister(0));
                __ llgfr(i.OutputRegister(), i.OutputRegister());
                break;
            case kS390_DoubleExtractHighWord32:
                __ lgdr(i.OutputRegister(), i.InputDoubleRegister(0));
                __ srlg(i.OutputRegister(), i.OutputRegister(), Operand(32));
                break;
            case kS390_DoubleInsertLowWord32:
                __ lgdr(kScratchReg, i.InputDoubleRegister(0));
                __ lr(kScratchReg, i.InputRegister(1));
                __ ldgr(i.OutputDoubleRegister(), kScratchReg);
                break;
            case kS390_DoubleInsertHighWord32:
                __ sllg(kScratchReg, i.InputRegister(1), Operand(32));
                __ lgdr(r0, i.InputDoubleRegister(0));
                __ lr(kScratchReg, r0);
                __ ldgr(i.OutputDoubleRegister(), kScratchReg);
                break;
            case kS390_DoubleConstruct:
                __ sllg(kScratchReg, i.InputRegister(0), Operand(32));
                __ lr(kScratchReg, i.InputRegister(1));

                // Bitwise convert from GPR to FPR
                __ ldgr(i.OutputDoubleRegister(), kScratchReg);
                break;
            case kS390_LoadWordS8:
                ASSEMBLE_LOAD_INTEGER(LoadB);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_BitcastFloat32ToInt32:
                ASSEMBLE_UNARY_OP(R_DInstr(MovFloatToInt), R_MInstr(LoadlW), nullInstr);
                break;
            case kS390_BitcastInt32ToFloat32:
                __ MovIntToFloat(i.OutputDoubleRegister(), i.InputRegister(0));
                break;
#if V8_TARGET_ARCH_S390X
            case kS390_BitcastDoubleToInt64:
                __ MovDoubleToInt64(i.OutputRegister(), i.InputDoubleRegister(0));
                break;
            case kS390_BitcastInt64ToDouble:
                __ MovInt64ToDouble(i.OutputDoubleRegister(), i.InputRegister(0));
                break;
#endif
            case kS390_LoadWordU8:
                ASSEMBLE_LOAD_INTEGER(LoadlB);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadWordU16:
                ASSEMBLE_LOAD_INTEGER(LoadLogicalHalfWordP);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadWordS16:
                ASSEMBLE_LOAD_INTEGER(LoadHalfWordP);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadWordU32:
                ASSEMBLE_LOAD_INTEGER(LoadlW);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadWordS32:
                ASSEMBLE_LOAD_INTEGER(LoadW);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadReverse16:
                ASSEMBLE_LOAD_INTEGER(lrvh);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadReverse32:
                ASSEMBLE_LOAD_INTEGER(lrv);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadReverse64:
                ASSEMBLE_LOAD_INTEGER(lrvg);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadReverse16RR:
                __ lrvr(i.OutputRegister(), i.InputRegister(0));
                __ rll(i.OutputRegister(), i.OutputRegister(), Operand(16));
                break;
            case kS390_LoadReverse32RR:
                __ lrvr(i.OutputRegister(), i.InputRegister(0));
                break;
            case kS390_LoadReverse64RR:
                __ lrvgr(i.OutputRegister(), i.InputRegister(0));
                break;
            case kS390_LoadWord64:
                ASSEMBLE_LOAD_INTEGER(lg);
                EmitWordLoadPoisoningIfNeeded(this, instr, i);
                break;
            case kS390_LoadAndTestWord32: {
                ASSEMBLE_LOADANDTEST32(ltr, lt_z);
                break;
            }
            case kS390_LoadAndTestWord64: {
                ASSEMBLE_LOADANDTEST64(ltgr, ltg);
                break;
            }
            case kS390_LoadFloat32:
                ASSEMBLE_LOAD_FLOAT(LoadFloat32);
                break;
            case kS390_LoadDouble:
                ASSEMBLE_LOAD_FLOAT(LoadDouble);
                break;
            case kS390_StoreWord8:
                ASSEMBLE_STORE_INTEGER(StoreByte);
                break;
            case kS390_StoreWord16:
                ASSEMBLE_STORE_INTEGER(StoreHalfWord);
                break;
            case kS390_StoreWord32:
                ASSEMBLE_STORE_INTEGER(StoreW);
                break;
#if V8_TARGET_ARCH_S390X
            case kS390_StoreWord64:
                ASSEMBLE_STORE_INTEGER(StoreP);
                break;
#endif
            case kS390_StoreReverse16:
                ASSEMBLE_STORE_INTEGER(strvh);
                break;
            case kS390_StoreReverse32:
                ASSEMBLE_STORE_INTEGER(strv);
                break;
            case kS390_StoreReverse64:
                ASSEMBLE_STORE_INTEGER(strvg);
                break;
            case kS390_StoreFloat32:
                ASSEMBLE_STORE_FLOAT32();
                break;
            case kS390_StoreDouble:
                ASSEMBLE_STORE_DOUBLE();
                break;
            case kS390_Lay:
                __ lay(i.OutputRegister(), i.MemoryOperand());
                break;
//         0x aa bb cc dd
// index =    3..2..1..0
#define ATOMIC_EXCHANGE(start, end, shift_amount, offset)                  \
    {                                                                      \
        Label do_cs;                                                       \
        __ LoadlW(output, MemOperand(r1, offset));                         \
        __ bind(&do_cs);                                                   \
        __ llgfr(r0, output);                                              \
        __ RotateInsertSelectBits(r0, value, Operand(start), Operand(end), \
            Operand(shift_amount), false);                                 \
        __ csy(output, r0, MemOperand(r1, offset));                        \
        __ bne(&do_cs, Label::kNear);                                      \
        __ srl(output, Operand(shift_amount));                             \
    }
#ifdef V8_TARGET_BIG_ENDIAN
#define ATOMIC_EXCHANGE_BYTE(i)                                      \
    {                                                                \
        constexpr int idx = (i);                                     \
        static_assert(idx <= 3 && idx >= 0, "idx is out of range!"); \
        constexpr int start = 32 + 8 * idx;                          \
        constexpr int end = start + 7;                               \
        constexpr int shift_amount = (3 - idx) * 8;                  \
        ATOMIC_EXCHANGE(start, end, shift_amount, -idx);             \
    }
#define ATOMIC_EXCHANGE_HALFWORD(i)                                  \
    {                                                                \
        constexpr int idx = (i);                                     \
        static_assert(idx <= 1 && idx >= 0, "idx is out of range!"); \
        constexpr int start = 32 + 16 * idx;                         \
        constexpr int end = start + 15;                              \
        constexpr int shift_amount = (1 - idx) * 16;                 \
        ATOMIC_EXCHANGE(start, end, shift_amount, -idx * 2);         \
    }
#else
#define ATOMIC_EXCHANGE_BYTE(i)                                      \
    {                                                                \
        constexpr int idx = (i);                                     \
        static_assert(idx <= 3 && idx >= 0, "idx is out of range!"); \
        constexpr int start = 32 + 8 * (3 - idx);                    \
        constexpr int end = start + 7;                               \
        constexpr int shift_amount = idx * 8;                        \
        ATOMIC_EXCHANGE(start, end, shift_amount, -idx);             \
    }
#define ATOMIC_EXCHANGE_HALFWORD(i)                                  \
    {                                                                \
        constexpr int idx = (i);                                     \
        static_assert(idx <= 1 && idx >= 0, "idx is out of range!"); \
        constexpr int start = 32 + 16 * (1 - idx);                   \
        constexpr int end = start + 15;                              \
        constexpr int shift_amount = idx * 16;                       \
        ATOMIC_EXCHANGE(start, end, shift_amount, -idx * 2);         \
    }
#endif
            case kS390_Word64AtomicExchangeUint8:
            case kWord32AtomicExchangeInt8:
            case kWord32AtomicExchangeUint8: {
                Register base = i.InputRegister(0);
                Register index = i.InputRegister(1);
                Register value = i.InputRegister(2);
                Register output = i.OutputRegister();
                Label three, two, one, done;
                __ la(r1, MemOperand(base, index));
                __ tmll(r1, Operand(3));
                __ b(Condition(1), &three);
                __ b(Condition(2), &two);
                __ b(Condition(4), &one);

                // end with 0b00
                ATOMIC_EXCHANGE_BYTE(0);
                __ b(&done);

                // ending with 0b01
                __ bind(&one);
                ATOMIC_EXCHANGE_BYTE(1);
                __ b(&done);

                // ending with 0b10
                __ bind(&two);
                ATOMIC_EXCHANGE_BYTE(2);
                __ b(&done);

                // ending with 0b11
                __ bind(&three);
                ATOMIC_EXCHANGE_BYTE(3);

                __ bind(&done);
                if (opcode == kWord32AtomicExchangeInt8) {
                    __ lgbr(output, output);
                } else {
                    __ llgcr(output, output);
                }
                break;
            }
            case kS390_Word64AtomicExchangeUint16:
            case kWord32AtomicExchangeInt16:
            case kWord32AtomicExchangeUint16: {
                Register base = i.InputRegister(0);
                Register index = i.InputRegister(1);
                Register value = i.InputRegister(2);
                Register output = i.OutputRegister();
                Label two, done;
                __ la(r1, MemOperand(base, index));
                __ tmll(r1, Operand(3));
                __ b(Condition(2), &two);

                // end with 0b00
                ATOMIC_EXCHANGE_HALFWORD(0);
                __ b(&done);

                // ending with 0b10
                __ bind(&two);
                ATOMIC_EXCHANGE_HALFWORD(1);

                __ bind(&done);
                if (opcode == kWord32AtomicExchangeInt16) {
                    __ lghr(output, output);
                } else {
                    __ llghr(output, output);
                }
                break;
            }
            case kS390_Word64AtomicExchangeUint32:
            case kWord32AtomicExchangeWord32: {
                Register base = i.InputRegister(0);
                Register index = i.InputRegister(1);
                Register value = i.InputRegister(2);
                Register output = i.OutputRegister();
                Label do_cs;
                __ lay(r1, MemOperand(base, index));
                __ LoadlW(output, MemOperand(r1));
                __ bind(&do_cs);
                __ cs(output, value, MemOperand(r1));
                __ bne(&do_cs, Label::kNear);
                break;
            }
            case kWord32AtomicCompareExchangeInt8:
                ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_BYTE(LoadB);
                break;
            case kS390_Word64AtomicCompareExchangeUint8:
            case kWord32AtomicCompareExchangeUint8:
                ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_BYTE(LoadlB);
                break;
            case kWord32AtomicCompareExchangeInt16:
                ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_HALFWORD(LoadHalfWordP);
                break;
            case kS390_Word64AtomicCompareExchangeUint16:
            case kWord32AtomicCompareExchangeUint16:
                ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_HALFWORD(LoadLogicalHalfWordP);
                break;
            case kS390_Word64AtomicCompareExchangeUint32:
            case kWord32AtomicCompareExchangeWord32:
                ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_WORD();
                break;
#define ATOMIC_BINOP_CASE(op, inst)                                           \
    case kWord32Atomic##op##Int8:                                             \
        ASSEMBLE_ATOMIC_BINOP_BYTE(inst, [&]() {                              \
            intptr_t shift_right = static_cast<intptr_t>(shift_amount);       \
            __ srlk(result, prev, Operand(shift_right));                      \
            __ LoadB(result, result);                                         \
        });                                                                   \
        break;                                                                \
    case kS390_Word64Atomic##op##Uint8:                                       \
    case kWord32Atomic##op##Uint8:                                            \
        ASSEMBLE_ATOMIC_BINOP_BYTE(inst, [&]() {                              \
            int rotate_left = shift_amount == 0 ? 0 : 64 - shift_amount;      \
            __ RotateInsertSelectBits(result, prev, Operand(56), Operand(63), \
                Operand(static_cast<intptr_t>(rotate_left)),                  \
                true);                                                        \
        });                                                                   \
        break;                                                                \
    case kWord32Atomic##op##Int16:                                            \
        ASSEMBLE_ATOMIC_BINOP_HALFWORD(inst, [&]() {                          \
            intptr_t shift_right = static_cast<intptr_t>(shift_amount);       \
            __ srlk(result, prev, Operand(shift_right));                      \
            __ LoadHalfWordP(result, result);                                 \
        });                                                                   \
        break;                                                                \
    case kS390_Word64Atomic##op##Uint16:                                      \
    case kWord32Atomic##op##Uint16:                                           \
        ASSEMBLE_ATOMIC_BINOP_HALFWORD(inst, [&]() {                          \
            int rotate_left = shift_amount == 0 ? 0 : 64 - shift_amount;      \
            __ RotateInsertSelectBits(result, prev, Operand(48), Operand(63), \
                Operand(static_cast<intptr_t>(rotate_left)),                  \
                true);                                                        \
        });                                                                   \
        break;
                ATOMIC_BINOP_CASE(Add, Add32)
                ATOMIC_BINOP_CASE(Sub, Sub32)
                ATOMIC_BINOP_CASE(And, And)
                ATOMIC_BINOP_CASE(Or, Or)
                ATOMIC_BINOP_CASE(Xor, Xor)
#undef ATOMIC_BINOP_CASE
            case kS390_Word64AtomicAddUint32:
            case kWord32AtomicAddWord32:
                ASSEMBLE_ATOMIC_BINOP_WORD(laa);
                break;
            case kS390_Word64AtomicSubUint32:
            case kWord32AtomicSubWord32:
                ASSEMBLE_ATOMIC_BINOP_WORD(LoadAndSub32);
                break;
            case kS390_Word64AtomicAndUint32:
            case kWord32AtomicAndWord32:
                ASSEMBLE_ATOMIC_BINOP_WORD(lan);
                break;
            case kS390_Word64AtomicOrUint32:
            case kWord32AtomicOrWord32:
                ASSEMBLE_ATOMIC_BINOP_WORD(lao);
                break;
            case kS390_Word64AtomicXorUint32:
            case kWord32AtomicXorWord32:
                ASSEMBLE_ATOMIC_BINOP_WORD(lax);
                break;
            case kS390_Word64AtomicAddUint64:
                ASSEMBLE_ATOMIC_BINOP_WORD64(laag);
                break;
            case kS390_Word64AtomicSubUint64:
                ASSEMBLE_ATOMIC_BINOP_WORD64(LoadAndSub64);
                break;
            case kS390_Word64AtomicAndUint64:
                ASSEMBLE_ATOMIC_BINOP_WORD64(lang);
                break;
            case kS390_Word64AtomicOrUint64:
                ASSEMBLE_ATOMIC_BINOP_WORD64(laog);
                break;
            case kS390_Word64AtomicXorUint64:
                ASSEMBLE_ATOMIC_BINOP_WORD64(laxg);
                break;
            case kS390_Word64AtomicExchangeUint64: {
                Register base = i.InputRegister(0);
                Register index = i.InputRegister(1);
                Register value = i.InputRegister(2);
                Register output = i.OutputRegister();
                Label do_cs;
                __ la(r1, MemOperand(base, index));
                __ lg(output, MemOperand(r1));
                __ bind(&do_cs);
                __ csg(output, value, MemOperand(r1));
                __ bne(&do_cs, Label::kNear);
                break;
            }
            case kS390_Word64AtomicCompareExchangeUint64:
                ASSEMBLE_ATOMIC64_COMP_EXCHANGE_WORD64();
                break;
            default:
                UNREACHABLE();
                break;
            }
            return kSuccess;
        } // NOLINT(readability/fn_size)

        // Assembles branches after an instruction.
        void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch)
        {
            S390OperandConverter i(this, instr);
            Label* tlabel = branch->true_label;
            Label* flabel = branch->false_label;
            ArchOpcode op = instr->arch_opcode();
            FlagsCondition condition = branch->condition;

            Condition cond = FlagsConditionToCondition(condition, op);
            if (op == kS390_CmpFloat || op == kS390_CmpDouble) {
                // check for unordered if necessary
                // Branching to flabel/tlabel according to what's expected by tests
                if (cond == le || cond == eq || cond == lt) {
                    __ bunordered(flabel);
                } else if (cond == gt || cond == ne || cond == ge) {
                    __ bunordered(tlabel);
                }
            }
            __ b(cond, tlabel);
            if (!branch->fallthru)
                __ b(flabel); // no fallthru to flabel.
        }

        void CodeGenerator::AssembleBranchPoisoning(FlagsCondition condition,
            Instruction* instr)
        {
            // TODO(John) Handle float comparisons (kUnordered[Not]Equal).
            if (condition == kUnorderedEqual || condition == kUnorderedNotEqual || condition == kOverflow || condition == kNotOverflow) {
                return;
            }

            condition = NegateFlagsCondition(condition);
            __ LoadImmP(r0, Operand::Zero());
            __ LoadOnConditionP(FlagsConditionToCondition(condition, kArchNop),
                kSpeculationPoisonRegister, r0);
        }

        void CodeGenerator::AssembleArchDeoptBranch(Instruction* instr,
            BranchInfo* branch)
        {
            AssembleArchBranch(instr, branch);
        }

        void CodeGenerator::AssembleArchJump(RpoNumber target)
        {
            if (!IsNextInAssemblyOrder(target))
                __ b(GetLabel(target));
        }

        void CodeGenerator::AssembleArchTrap(Instruction* instr,
            FlagsCondition condition)
        {
            class OutOfLineTrap final : public OutOfLineCode {
            public:
                OutOfLineTrap(CodeGenerator* gen, Instruction* instr)
                    : OutOfLineCode(gen)
                    , instr_(instr)
                    , gen_(gen)
                {
                }

                void Generate() final
                {
                    S390OperandConverter i(gen_, instr_);
                    TrapId trap_id = static_cast<TrapId>(i.InputInt32(instr_->InputCount() - 1));
                    GenerateCallToTrap(trap_id);
                }

            private:
                void GenerateCallToTrap(TrapId trap_id)
                {
                    if (trap_id == TrapId::kInvalid) {
                        // We cannot test calls to the runtime in cctest/test-run-wasm.
                        // Therefore we emit a call to C here instead of a call to the runtime.
                        // We use the context register as the scratch register, because we do
                        // not have a context here.
                        __ PrepareCallCFunction(0, 0, cp);
                        __ CallCFunction(
                            ExternalReference::wasm_call_trap_callback_for_testing(), 0);
                        __ LeaveFrame(StackFrame::WASM_COMPILED);
                        auto call_descriptor = gen_->linkage()->GetIncomingDescriptor();
                        int pop_count = static_cast<int>(call_descriptor->StackParameterCount());
                        __ Drop(pop_count);
                        __ Ret();
                    } else {
                        gen_->AssembleSourcePosition(instr_);
                        // A direct call to a wasm runtime stub defined in this module.
                        // Just encode the stub index. This will be patched when the code
                        // is added to the native module and copied into wasm code space.
                        __ Call(static_cast<Address>(trap_id), RelocInfo::WASM_STUB_CALL);
                        ReferenceMap* reference_map = new (gen_->zone()) ReferenceMap(gen_->zone());
                        gen_->RecordSafepoint(reference_map, Safepoint::kSimple,
                            Safepoint::kNoLazyDeopt);
                        if (FLAG_debug_code) {
                            __ stop(GetAbortReason(AbortReason::kUnexpectedReturnFromWasmTrap));
                        }
                    }
                }

                Instruction* instr_;
                CodeGenerator* gen_;
            };
            auto ool = new (zone()) OutOfLineTrap(this, instr);
            Label* tlabel = ool->entry();
            Label end;

            ArchOpcode op = instr->arch_opcode();
            Condition cond = FlagsConditionToCondition(condition, op);
            if (op == kS390_CmpFloat || op == kS390_CmpDouble) {
                // check for unordered if necessary
                if (cond == le || cond == eq || cond == lt) {
                    __ bunordered(&end);
                } else if (cond == gt || cond == ne || cond == ge) {
                    __ bunordered(tlabel);
                }
            }
            __ b(cond, tlabel);
            __ bind(&end);
        }

        // Assembles boolean materializations after an instruction.
        void CodeGenerator::AssembleArchBoolean(Instruction* instr,
            FlagsCondition condition)
        {
            S390OperandConverter i(this, instr);
            ArchOpcode op = instr->arch_opcode();
            bool check_unordered = (op == kS390_CmpDouble || op == kS390_CmpFloat);

            // Overflow checked for add/sub only.
            DCHECK((condition != kOverflow && condition != kNotOverflow) || (op == kS390_Add32 || op == kS390_Add64 || op == kS390_Sub32 || op == kS390_Sub64 || op == kS390_Mul32));

            // Materialize a full 32-bit 1 or 0 value. The result register is always the
            // last output of the instruction.
            DCHECK_NE(0u, instr->OutputCount());
            Register reg = i.OutputRegister(instr->OutputCount() - 1);
            Condition cond = FlagsConditionToCondition(condition, op);
            Label done;
            if (check_unordered) {
                __ LoadImmP(reg, (cond == eq || cond == le || cond == lt) ? Operand::Zero() : Operand(1));
                __ bunordered(&done);
            }

            // TODO(john.yan): use load imm high on condition here
            __ LoadImmP(reg, Operand::Zero());
            __ LoadImmP(kScratchReg, Operand(1));
            // locr is sufficient since reg's upper 32 is guarrantee to be 0
            __ locr(cond, reg, kScratchReg);
            __ bind(&done);
        }

        void CodeGenerator::AssembleArchBinarySearchSwitch(Instruction* instr)
        {
            S390OperandConverter i(this, instr);
            Register input = i.InputRegister(0);
            std::vector<std::pair<int32_t, Label*>> cases;
            for (size_t index = 2; index < instr->InputCount(); index += 2) {
                cases.push_back({ i.InputInt32(index + 0), GetLabel(i.InputRpo(index + 1)) });
            }
            AssembleArchBinarySearchSwitchRange(input, i.InputRpo(1), cases.data(),
                cases.data() + cases.size());
        }

        void CodeGenerator::AssembleArchLookupSwitch(Instruction* instr)
        {
            S390OperandConverter i(this, instr);
            Register input = i.InputRegister(0);
            for (size_t index = 2; index < instr->InputCount(); index += 2) {
                __ Cmp32(input, Operand(i.InputInt32(index + 0)));
                __ beq(GetLabel(i.InputRpo(index + 1)));
            }
            AssembleArchJump(i.InputRpo(1));
        }

        void CodeGenerator::AssembleArchTableSwitch(Instruction* instr)
        {
            S390OperandConverter i(this, instr);
            Register input = i.InputRegister(0);
            int32_t const case_count = static_cast<int32_t>(instr->InputCount() - 2);
            Label** cases = zone()->NewArray<Label*>(case_count);
            for (int32_t index = 0; index < case_count; ++index) {
                cases[index] = GetLabel(i.InputRpo(index + 2));
            }
            Label* const table = AddJumpTable(cases, case_count);
            __ CmpLogicalP(input, Operand(case_count));
            __ bge(GetLabel(i.InputRpo(1)));
            __ larl(kScratchReg, table);
            __ ShiftLeftP(r1, input, Operand(kSystemPointerSizeLog2));
            __ LoadP(kScratchReg, MemOperand(kScratchReg, r1));
            __ Jump(kScratchReg);
        }

        void CodeGenerator::FinishFrame(Frame* frame)
        {
            auto call_descriptor = linkage()->GetIncomingDescriptor();
            const RegList double_saves = call_descriptor->CalleeSavedFPRegisters();

            // Save callee-saved Double registers.
            if (double_saves != 0) {
                frame->AlignSavedCalleeRegisterSlots();
                DCHECK_EQ(kNumCalleeSavedDoubles,
                    base::bits::CountPopulation(double_saves));
                frame->AllocateSavedCalleeRegisterSlots(kNumCalleeSavedDoubles * (kDoubleSize / kSystemPointerSize));
            }
            // Save callee-saved registers.
            const RegList saves = call_descriptor->CalleeSavedRegisters();
            if (saves != 0) {
                // register save area does not include the fp or constant pool pointer.
                const int num_saves = kNumCalleeSaved - 1;
                DCHECK(num_saves == base::bits::CountPopulation(saves));
                frame->AllocateSavedCalleeRegisterSlots(num_saves);
            }
        }

        void CodeGenerator::AssembleConstructFrame()
        {
            auto call_descriptor = linkage()->GetIncomingDescriptor();

            if (frame_access_state()->has_frame()) {
                if (call_descriptor->IsCFunctionCall()) {
                    __ Push(r14, fp);
                    __ LoadRR(fp, sp);
                } else if (call_descriptor->IsJSFunctionCall()) {
                    __ Prologue(ip);
                    if (call_descriptor->PushArgumentCount()) {
                        __ Push(kJavaScriptCallArgCountRegister);
                    }
                } else {
                    StackFrame::Type type = info()->GetOutputStackFrameType();
                    // TODO(mbrandy): Detect cases where ip is the entrypoint (for
                    // efficient intialization of the constant pool pointer register).
                    __ StubPrologue(type);
                    if (call_descriptor->IsWasmFunctionCall()) {
                        __ Push(kWasmInstanceRegister);
                    } else if (call_descriptor->IsWasmImportWrapper()) {
                        // WASM import wrappers are passed a tuple in the place of the instance.
                        // Unpack the tuple into the instance and the target callable.
                        // This must be done here in the codegen because it cannot be expressed
                        // properly in the graph.
                        __ LoadP(kJSFunctionRegister,
                            FieldMemOperand(kWasmInstanceRegister, Tuple2::kValue2Offset));
                        __ LoadP(kWasmInstanceRegister,
                            FieldMemOperand(kWasmInstanceRegister, Tuple2::kValue1Offset));
                        __ Push(kWasmInstanceRegister);
                    }
                }
            }

            int required_slots = frame()->GetTotalFrameSlotCount() - call_descriptor->CalculateFixedFrameSize();
            if (info()->is_osr()) {
                // TurboFan OSR-compiled functions cannot be entered directly.
                __ Abort(AbortReason::kShouldNotDirectlyEnterOsrFunction);

                // Unoptimized code jumps directly to this entrypoint while the unoptimized
                // frame is still on the stack. Optimized code uses OSR values directly from
                // the unoptimized frame. Thus, all that needs to be done is to allocate the
                // remaining stack slots.
                if (FLAG_code_comments)
                    __ RecordComment("-- OSR entrypoint --");
                osr_pc_offset_ = __ pc_offset();
                required_slots -= osr_helper()->UnoptimizedFrameSlots();
                ResetSpeculationPoison();
            }

            const RegList saves_fp = call_descriptor->CalleeSavedFPRegisters();
            const RegList saves = call_descriptor->CalleeSavedRegisters();

            if (required_slots > 0) {
                if (info()->IsWasm() && required_slots > 128) {
                    // For WebAssembly functions with big frames we have to do the stack
                    // overflow check before we construct the frame. Otherwise we may not
                    // have enough space on the stack to call the runtime for the stack
                    // overflow.
                    Label done;

                    // If the frame is bigger than the stack, we throw the stack overflow
                    // exception unconditionally. Thereby we can avoid the integer overflow
                    // check in the condition code.
                    if ((required_slots * kSystemPointerSize) < (FLAG_stack_size * 1024)) {
                        Register scratch = r1;
                        __ LoadP(
                            scratch,
                            FieldMemOperand(kWasmInstanceRegister,
                                WasmInstanceObject::kRealStackLimitAddressOffset));
                        __ LoadP(scratch, MemOperand(scratch));
                        __ AddP(scratch, scratch, Operand(required_slots * kSystemPointerSize));
                        __ CmpLogicalP(sp, scratch);
                        __ bge(&done);
                    }

                    __ Call(wasm::WasmCode::kWasmStackOverflow, RelocInfo::WASM_STUB_CALL);
                    // We come from WebAssembly, there are no references for the GC.
                    ReferenceMap* reference_map = new (zone()) ReferenceMap(zone());
                    RecordSafepoint(reference_map, Safepoint::kSimple,
                        Safepoint::kNoLazyDeopt);
                    if (FLAG_debug_code) {
                        __ stop(GetAbortReason(AbortReason::kUnexpectedReturnFromThrow));
                    }

                    __ bind(&done);
                }

                // Skip callee-saved and return slots, which are pushed below.
                required_slots -= base::bits::CountPopulation(saves);
                required_slots -= frame()->GetReturnSlotCount();
                required_slots -= (kDoubleSize / kSystemPointerSize) * base::bits::CountPopulation(saves_fp);
                __ lay(sp, MemOperand(sp, -required_slots * kSystemPointerSize));
            }

            // Save callee-saved Double registers.
            if (saves_fp != 0) {
                __ MultiPushDoubles(saves_fp);
                DCHECK_EQ(kNumCalleeSavedDoubles, base::bits::CountPopulation(saves_fp));
            }

            // Save callee-saved registers.
            if (saves != 0) {
                __ MultiPush(saves);
                // register save area does not include the fp or constant pool pointer.
            }

            const int returns = frame()->GetReturnSlotCount();
            if (returns != 0) {
                // Create space for returns.
                __ lay(sp, MemOperand(sp, -returns * kSystemPointerSize));
            }
        }

        void CodeGenerator::AssembleReturn(InstructionOperand* pop)
        {
            auto call_descriptor = linkage()->GetIncomingDescriptor();
            int pop_count = static_cast<int>(call_descriptor->StackParameterCount());

            const int returns = frame()->GetReturnSlotCount();
            if (returns != 0) {
                // Create space for returns.
                __ lay(sp, MemOperand(sp, returns * kSystemPointerSize));
            }

            // Restore registers.
            const RegList saves = call_descriptor->CalleeSavedRegisters();
            if (saves != 0) {
                __ MultiPop(saves);
            }

            // Restore double registers.
            const RegList double_saves = call_descriptor->CalleeSavedFPRegisters();
            if (double_saves != 0) {
                __ MultiPopDoubles(double_saves);
            }

            S390OperandConverter g(this, nullptr);
            if (call_descriptor->IsCFunctionCall()) {
                AssembleDeconstructFrame();
            } else if (frame_access_state()->has_frame()) {
                // Canonicalize JSFunction return sites for now unless they have an variable
                // number of stack slot pops
                if (pop->IsImmediate() && g.ToConstant(pop).ToInt32() == 0) {
                    if (return_label_.is_bound()) {
                        __ b(&return_label_);
                        return;
                    } else {
                        __ bind(&return_label_);
                        AssembleDeconstructFrame();
                    }
                } else {
                    AssembleDeconstructFrame();
                }
            }
            if (pop->IsImmediate()) {
                pop_count += g.ToConstant(pop).ToInt32();
            } else {
                __ Drop(g.ToRegister(pop));
            }
            __ Drop(pop_count);
            __ Ret();
        }

        void CodeGenerator::FinishCode() { }

        void CodeGenerator::AssembleMove(InstructionOperand* source,
            InstructionOperand* destination)
        {
            S390OperandConverter g(this, nullptr);
            // Dispatch on the source and destination operand kinds.  Not all
            // combinations are possible.
            if (source->IsRegister()) {
                DCHECK(destination->IsRegister() || destination->IsStackSlot());
                Register src = g.ToRegister(source);
                if (destination->IsRegister()) {
                    __ Move(g.ToRegister(destination), src);
                } else {
                    __ StoreP(src, g.ToMemOperand(destination));
                }
            } else if (source->IsStackSlot()) {
                DCHECK(destination->IsRegister() || destination->IsStackSlot());
                MemOperand src = g.ToMemOperand(source);
                if (destination->IsRegister()) {
                    __ LoadP(g.ToRegister(destination), src);
                } else {
                    Register temp = kScratchReg;
                    __ LoadP(temp, src, r0);
                    __ StoreP(temp, g.ToMemOperand(destination));
                }
            } else if (source->IsConstant()) {
                Constant src = g.ToConstant(source);
                if (destination->IsRegister() || destination->IsStackSlot()) {
                    Register dst = destination->IsRegister() ? g.ToRegister(destination) : kScratchReg;
                    switch (src.type()) {
                    case Constant::kInt32:
#if V8_TARGET_ARCH_S390X
                        if (false) {
#else
                        if (RelocInfo::IsWasmReference(src.rmode())) {
#endif
                            __ mov(dst, Operand(src.ToInt32(), src.rmode()));
                        } else {
                            __ Load(dst, Operand(src.ToInt32()));
                        }
                        break;
                    case Constant::kInt64:
#if V8_TARGET_ARCH_S390X
                        if (RelocInfo::IsWasmReference(src.rmode())) {
                            __ mov(dst, Operand(src.ToInt64(), src.rmode()));
                        } else {
                            __ Load(dst, Operand(src.ToInt64()));
                        }
#else
                        __ mov(dst, Operand(src.ToInt64()));
#endif // V8_TARGET_ARCH_S390X
                        break;
                    case Constant::kFloat32:
                        __ mov(dst, Operand::EmbeddedNumber(src.ToFloat32()));
                        break;
                    case Constant::kFloat64:
                        __ mov(dst, Operand::EmbeddedNumber(src.ToFloat64().value()));
                        break;
                    case Constant::kExternalReference:
                        __ Move(dst, src.ToExternalReference());
                        break;
                    case Constant::kDelayedStringConstant:
                        __ mov(dst, Operand::EmbeddedStringConstant(src.ToDelayedStringConstant()));
                        break;
                    case Constant::kHeapObject: {
                        Handle<HeapObject> src_object = src.ToHeapObject();
                        RootIndex index;
                        if (IsMaterializableFromRoot(src_object, &index)) {
                            __ LoadRoot(dst, index);
                        } else {
                            __ Move(dst, src_object);
                        }
                        break;
                    }
                    case Constant::kRpoNumber:
                        UNREACHABLE(); // TODO(dcarney): loading RPO constants on S390.
                        break;
                    }
                    if (destination->IsStackSlot()) {
                        __ StoreP(dst, g.ToMemOperand(destination), r0);
                    }
                } else {
                    DoubleRegister dst = destination->IsFPRegister()
                        ? g.ToDoubleRegister(destination)
                        : kScratchDoubleReg;
                    double value = (src.type() == Constant::kFloat32)
                        ? src.ToFloat32()
                        : src.ToFloat64().value();
                    if (src.type() == Constant::kFloat32) {
                        __ LoadFloat32Literal(dst, src.ToFloat32(), kScratchReg);
                    } else {
                        __ LoadDoubleLiteral(dst, value, kScratchReg);
                    }

                    if (destination->IsFloatStackSlot()) {
                        __ StoreFloat32(dst, g.ToMemOperand(destination));
                    } else if (destination->IsDoubleStackSlot()) {
                        __ StoreDouble(dst, g.ToMemOperand(destination));
                    }
                }
            } else if (source->IsFPRegister()) {
                DoubleRegister src = g.ToDoubleRegister(source);
                if (destination->IsFPRegister()) {
                    DoubleRegister dst = g.ToDoubleRegister(destination);
                    __ Move(dst, src);
                } else {
                    DCHECK(destination->IsFPStackSlot());
                    LocationOperand* op = LocationOperand::cast(source);
                    if (op->representation() == MachineRepresentation::kFloat64) {
                        __ StoreDouble(src, g.ToMemOperand(destination));
                    } else {
                        __ StoreFloat32(src, g.ToMemOperand(destination));
                    }
                }
            } else if (source->IsFPStackSlot()) {
                DCHECK(destination->IsFPRegister() || destination->IsFPStackSlot());
                MemOperand src = g.ToMemOperand(source);
                if (destination->IsFPRegister()) {
                    LocationOperand* op = LocationOperand::cast(source);
                    if (op->representation() == MachineRepresentation::kFloat64) {
                        __ LoadDouble(g.ToDoubleRegister(destination), src);
                    } else {
                        __ LoadFloat32(g.ToDoubleRegister(destination), src);
                    }
                } else {
                    LocationOperand* op = LocationOperand::cast(source);
                    DoubleRegister temp = kScratchDoubleReg;
                    if (op->representation() == MachineRepresentation::kFloat64) {
                        __ LoadDouble(temp, src);
                        __ StoreDouble(temp, g.ToMemOperand(destination));
                    } else {
                        __ LoadFloat32(temp, src);
                        __ StoreFloat32(temp, g.ToMemOperand(destination));
                    }
                }
            } else {
                UNREACHABLE();
            }
        }

        // Swaping contents in source and destination.
        // source and destination could be:
        //   Register,
        //   FloatRegister,
        //   DoubleRegister,
        //   StackSlot,
        //   FloatStackSlot,
        //   or DoubleStackSlot
        void CodeGenerator::AssembleSwap(InstructionOperand* source,
            InstructionOperand* destination)
        {
            S390OperandConverter g(this, nullptr);
            if (source->IsRegister()) {
                Register src = g.ToRegister(source);
                if (destination->IsRegister()) {
                    __ SwapP(src, g.ToRegister(destination), kScratchReg);
                } else {
                    DCHECK(destination->IsStackSlot());
                    __ SwapP(src, g.ToMemOperand(destination), kScratchReg);
                }
            } else if (source->IsStackSlot()) {
                DCHECK(destination->IsStackSlot());
                __ SwapP(g.ToMemOperand(source), g.ToMemOperand(destination), kScratchReg,
                    r0);
            } else if (source->IsFloatRegister()) {
                DoubleRegister src = g.ToDoubleRegister(source);
                if (destination->IsFloatRegister()) {
                    __ SwapFloat32(src, g.ToDoubleRegister(destination), kScratchDoubleReg);
                } else {
                    DCHECK(destination->IsFloatStackSlot());
                    __ SwapFloat32(src, g.ToMemOperand(destination), kScratchDoubleReg);
                }
            } else if (source->IsDoubleRegister()) {
                DoubleRegister src = g.ToDoubleRegister(source);
                if (destination->IsDoubleRegister()) {
                    __ SwapDouble(src, g.ToDoubleRegister(destination), kScratchDoubleReg);
                } else {
                    DCHECK(destination->IsDoubleStackSlot());
                    __ SwapDouble(src, g.ToMemOperand(destination), kScratchDoubleReg);
                }
            } else if (source->IsFloatStackSlot()) {
                DCHECK(destination->IsFloatStackSlot());
                __ SwapFloat32(g.ToMemOperand(source), g.ToMemOperand(destination),
                    kScratchDoubleReg, d0);
            } else if (source->IsDoubleStackSlot()) {
                DCHECK(destination->IsDoubleStackSlot());
                __ SwapDouble(g.ToMemOperand(source), g.ToMemOperand(destination),
                    kScratchDoubleReg, d0);
            } else if (source->IsSimd128Register()) {
                UNREACHABLE();
            } else {
                UNREACHABLE();
            }
        }

        void CodeGenerator::AssembleJumpTable(Label** targets, size_t target_count)
        {
            for (size_t index = 0; index < target_count; ++index) {
                __ emit_label_addr(targets[index]);
            }
        }

#undef __

    } // namespace compiler
} // namespace internal
} // namespace v8
